Remove Circle CI config.yml

As it is not used and hence is misleading.

.circleci/config.yml

@@ -1,31 +0,0 @@
-version: 2
-
-jobs:
-  build:
-    docker:
-      - image: rust:1.34.0-slim
-
-    steps:
-      - checkout
-      - run:
-          name: Install Dependencies
-          command: |
-            apt-get update
-            apt-get install -y clang cmake libsnappy-dev
-            rustup component add rustfmt
-            rustup component add clippy
-      - run:
-          name: Format
-          command: cargo fmt --all -- --check
-      - run:
-          name: Check
-          command: cargo check --all
-      - run:
-          name: Clippy
-          command: cargo clippy --all
-      - run:
-          name: Build
-          command: cargo build --all
-      - run:
-          name: Test
-          command: cargo test --all