Aiuti

Change Log:
- Fixed `FileLock.acquire_ctx()` only releasing on error

Change Log:
- Updated all code to pass MyPy in strict mode
- Implemented a workaround for `BufferAsyncCalls.wait()` hanging on 3.7

Change Log:
- Added new asyncio functions: `ensure_aw()`, `loop_in_thread()`, and `run_aw_threadsafe()`
- Added `BufferAsyncCalls.wait_from_anywhere()` to support waiting for the buffer from potentially another thread
- Fixed potential deadlock in `to_sync_iter()` which could occur if the target event loop didn't continue to run

Change Log:
- Added `aiuti.itertools` module with `exhaust()` and `split()`
- Added additional queuing methods to `BufferAsyncCalls`:
- `.await_()` for queuing an awaitable
- `.map()` for queuing from an iterable
- `.amap()` for queuing from an async iterable

Change Log:
- Added a thread-safe filelock implementation

Initial Release