Add Bloop config, documentation (#412)

CONTRIBUTING.md

@@ -10,6 +10,62 @@ It's possible to communicate with other developers through a variety of communic
 - [Bitcoin-S Gitter](https://gitter.im/bitcoin-s-core/)
 - [#bitcoin-scala](https://webchat.freenode.net/?channels=bitcoin-scala) on IRC Freenode
 
+## Developer productivity
+
+### Bloop
+
+If you're tired of waiting around for sbt all day, there's a new,
+cool kid on the block. It is called [Bloop](https://scalacenter.github.io/bloop/),
+and it makes compilations in general faster, and in particular
+incremental, small compilation units (which greatly help editor
+performance). Bloop is a server that runs in the background of
+your computer, and keeps several "hot" JVMs running at all
+times. These JVMs serve compilation requests. Because the JVMs
+are running in the background you avoid the startup lag, and you
+also get code that's already [JIT compiled](https://en.wikipedia.org/wiki/Just-in-time_compilation)
+for you.
+
+The documentation on Bloops [site](https://scalacenter.github.io/bloop/) is good, but here is the highlights:
+
+1. Install Bloop by doing step 1 & 2 in the [official guide](https://scalacenter.github.io/bloop/setup#universal)
+2. Enable the Bloop background daemon
+   1. macOS:
+   ```bash
+   $ brew services start bloop
+   ```
+   2. Ubuntu:
+   ```bash
+   $ systemctl --user enable $HOME/.bloop/systemd/bloop.service
+   $ systemctl --user daemon-reload
+   $ systemctl --user start bloop
+   ```
+3. Enable shell completion for the Bloop CLI
+   1. Bash:
+   ```bash
+   $ echo '. $HOME/.bloop/bash/bloop' >> $HOME/.bash_profile
+   ```
+   2. Zsh:
+   ```bash
+   $ echo 'autoload -U compinit' >> $HOME/.zshrc
+   $ echo 'fpath=($HOME/.bloop/zsh $fpath)' >> $HOME/.bashrc
+   $ echo 'compinit' >> $HOME/.bashrc
+   ```
+   3. Fish:
+   ```bash
+   $ ln -s $HOME/.bloop/fish/bloop.fish ~/.config/fish/completions/bloop.fish
+   ```
+4. Generate configuration files
+   ```bash
+   $ sbt bloopInstall
+   ```
+5. Import Bitcoin-S into IntelliJ again, as a bsp (Build Server Protocol) project (instead of a sbt project). Make sure you're running on the most recent IntelliJ and Scala plugin. See [official docs](https://scalacenter.github.io/bloop/docs/ides/intellij) for details.
+6. _(Bonus step):_ Lightning fast recompilations on file save:
+   ```bash
+   $ bloop compile --project <name of module your're working on> --watch
+   ```
+
+Your editor should now be much faster and require less resources :tada:
+
 ## Documentation
 
 One of the goals of Bitcoin-S is having useful and well-formatted Scaladoc comments on classes,

build.sbt

@@ -111,6 +111,14 @@ lazy val commonSettings = List(
     .isDefined)
 )
 
+lazy val commonTestSettings = Seq(
+  publish / skip := true,
+) ++ commonSettings
+
+lazy val commonProdSettings = Seq(
+  Test / bloopGenerate := None
+) ++ commonSettings
+
 lazy val root = project
   .in(file("."))
   .aggregate(
@@ -152,16 +160,15 @@ lazy val secp256k1jni = project
 
 lazy val core = project
   .in(file("core"))
-  .settings(commonSettings: _*)
+  .settings(commonProdSettings: _*)
   .dependsOn(
     secp256k1jni
   ).enablePlugins()
 
 lazy val coreTest = project
   .in(file("core-test"))
-  .settings(commonSettings: _*)
+  .settings(commonTestSettings: _*)
   .settings(
-    skip in publish := true,
     name := "bitcoin-s-core-test"
   ).dependsOn(
     core,
@@ -180,7 +187,7 @@ lazy val zmq = project
 
 lazy val bitcoindRpc = project
   .in(file("bitcoind-rpc"))
-  .settings(commonSettings: _*)
+  .settings(commonProdSettings: _*)
   .settings(
     name := "bitcoin-s-bitcoind-rpc",
     libraryDependencies ++= Deps.bitcoindRpc)
@@ -189,10 +196,10 @@ lazy val bitcoindRpc = project
 
 lazy val bitcoindRpcTest = project
   .in(file("bitcoind-rpc-test"))
-  .settings(commonSettings: _*)
-  .settings(libraryDependencies ++= Deps.bitcoindRpcTest,
-    name := "bitcoin-s-bitcoind-rpc-test",
-    skip in publish := true)
+  .settings(commonTestSettings: _*)
+  .settings(
+    libraryDependencies ++= Deps.bitcoindRpcTest,
+    name := "bitcoin-s-bitcoind-rpc-test")
   .dependsOn(testkit)
   .enablePlugins()
 
@@ -212,7 +219,7 @@ lazy val bench = project
 
 lazy val eclairRpc = project
   .in(file("eclair-rpc"))
-  .settings(commonSettings: _*)
+  .settings(commonProdSettings: _*)
   .settings(
     name := "bitcoin-s-eclair-rpc",
     libraryDependencies ++= Deps.eclairRpc)
@@ -223,17 +230,16 @@ lazy val eclairRpc = project
 
 lazy val eclairRpcTest = project
   .in(file("eclair-rpc-test"))
-  .settings(commonSettings: _*)
+  .settings(commonTestSettings: _*)
   .settings(libraryDependencies ++= Deps.eclairRpcTest,
     name := "bitcoin-s-eclair-rpc-test",
-    skip in publish := true
   )
   .dependsOn(testkit)
   .enablePlugins()
 
 lazy val testkit = project
   .in(file("testkit"))
-  .settings(commonSettings: _*)
+  .settings(commonProdSettings: _*)
   .dependsOn(
     core,
     bitcoindRpc,
@@ -243,10 +249,10 @@ lazy val testkit = project
 
 lazy val doc = project
   .in(file("doc"))
+  .settings(commonTestSettings: _*)
   .settings(
     name := "bitcoin-s-doc",
     libraryDependencies ++= Deps.doc,
-    skip in publish := true
   )
   .dependsOn(
     secp256k1jni,

project/plugins.sbt

@@ -28,3 +28,6 @@ addSbtPlugin(
   "com.thoughtworks.sbt-api-mappings" % "sbt-api-mappings" % "latest.release")
 
 addSbtPlugin("com.typesafe.sbt" % "sbt-git" % "0.9.3")
+
+// bloop is a build server, enabling faster builds and more rapid dev feedback
+addSbtPlugin("ch.epfl.scala" % "sbt-bloop" % "1.2.5")