Belay

Features
* New command `belay run` to run a file on-device.
* New command `belay exec` to execute a python string on-device.
* `sync` improvements:
* New argument `dst`; folder to sync file into. Defaults to `"/"`;
* New argument `ignore`; uses gitignore pattern matching to ignore files during sync. Defaults to common undesired files.
* New argument `mpy_cross_binary`; if provided, will compile .py files into .mpy prior to syncing.
* Can now sync a single file. Other files will not be deleted when syncing a single file.
* Can now keeps all untouched files if `keep=True`.
* Changed file hashing function from FNV-1a-64bit to FNV-1a-32bit for speed. Optimized implementation with `native` and `viper` decorators for a large speed boost
* Parallelized pre-processing operations for faster syncs.
* Misc bug fixes; a lot more unit testing.

Features

* Added the `identify` command to the cli. This executes `info`, but also blinks an LED (or neopixel) on the board. Works with both circuitpython and micropython. This is useful for identifying which board is which when using multiple devices.

Features
* Added support to automatically reconnect to a device upon a temporary disconnect. To activate, provide a non-zero value to the `attempts` keyword argument when creating the `belay.Device`. See docs for details and limitations.
* Added `sys.platform` information to the `Implementation` data structure.
* Add `info` cli command to see device `Implementation` information. Useful for quickly checking what firmware is running on-device.

Features
* CircuitPython is now supported.
* Since CircuitPython doesn't guarentee `hashlib` to be builtin, the file hashing function for syncing operations has been changed from sha256 to [64-bit FNV-1a](https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function). FNV-1a was selected for its incredibly terse implementation, and reasonable performance for simply detecting if a file has changed.
* New attribute [`device.implementation`](https://belay.readthedocs.io/en/latest/api.html#belay.Implementation) contains the name (`micropython` or `circuitpython`) and version of firmware running on-device.

Bug Fixes
* Fixed an off-by-one error for the final line reported in a stacktrace when an exception is raised on-device. This only occurred when the `task` or `thread` decorators were used.

Features
* Added a new command line program, `belay`. Run `belay --help` for more information.
* Currently only one supported action, `sync`, to sync a folder to the device's root.
* Added the public method `Device.close()` to gracefully close device connection (Partially addresses 14).
* Support decorating generator functions with the `task` decorator (Addresses 15).
* `print` calls from device are now forwarded to host's `stdout`. User print statements **must not** begin with `_BELAY`, as these are reserved for internal use.

Features
* Added `belay.AuthenticationError` for when password is incorrect for WebREPL.

Bug Fixes
* Fixed folder creation during `Device.sync`