* Refactor AsyncUtil to just use an execution context rather than an actor system
* Create testkit-core, start moving data structures over to testkit-core
* WIP, getting rid of the hard dependency on BitcoinSAsyncTest and akka
* Rework test traits to not be dependnent on akka, move BaseAsyncTest into testkitCore, add a test trait that just uses the default scala executionContext
* Get everything compiling
* Move logback-test.xml to testkit-core so it applies to coreTest,cryptoTest as well
* Cleanup rebase issues
* Fix Deps.scala
* Address ben's code review
* Segregate jvm settings and compiler settings
* Filter out -Xfatal-warning for scalajs for now since there is a ton of errors
* Move maintainer settings into CommonSettings.settings
Added OutputReference and introduced public key computation on SPKs
Made InputInfo into an ADT
Made UTXOSpendingInfo use InputInfo
Replaced UTXOSpendingInfo with NewSpendingInfo and got non-test things compiling
Made aliases for (NewSpendingInfo/NewSpendingInfoFull/NewSpendingInfoSingle)[InputInfo]
Got rid of source code mention of UTXOSpendingInfo
sbt compile passes
tests compile
Fixed all coreTest tests
Renamed to UTXOInfo
Some cleanup
Moved redeem script and script witness accessors to companion object
Responded to code review
Added OutputReference and scaladocs
Moved p2pkhPreImageOpt downstream and generalized to hashPreImages
Fixed adding-spks.md
Fixed psbts.md and txbuilder.md
Renamed UTXOInfo
Apply renaming to docs
* Added crypto project and decoupled BitcoinSLogger from NetworkElement
Decoupled BitcoinSLogger from Factory
Moved NetworkElement into crypto project
Moved Factory and BitcoinSUtil (renamed to BytesUtil) to crypto project
Moved MaskedToString to crypto project
Added BytesUtil to imports and cleaned up CryptoUtil.recoverPoint
Moved the rest of crypto stuff to the crypto project
Moved crypto tests to crypto-test project
* Added documentation for crypto project
* Added a document explaining how to add new script types.
* built website
* Added a doc explaining the differences between full and single signing
* Added design philosophy section
* Responded to review
* mdoc now compiles the code within adding-spks.md, with some caveats surrounding sealed traits
* Added explanitory comment