Version bump to build using updated dependencies

Skips v0.5.3 because I mistakenly created a v0.5.3 tag that points to a
commit that didn't update binary_version to v0.5.3

Version bump to build using updated dependencies

Version bump to build using updated dependencies

binary: fix boolean environment variable parsing

Implement g:nvim_ghost_keep_buffers

When set to 1, buffers won't be deleted when the connection is closed
from the browser side. This avoids any data loss in case of browser
crashes.

Added :GhostTextStop when autostart = 0

Release v0.4.1

- Fix the bug that was fixed in v0.3.2 and reintroduced in v0.4.0
- Reduce default verbosity of logs. We can get more verbose logs on
  demand by setting the environment variable NVIM_GHOST_VERBOSE_LOGGING

Revert back to threading

Multiprocessing is hard. Especially when you include Windows in the mix.
But this was a good exercise. It showed me how messed up my code is.

Notes to future self:
- The reason i've abandoned the path of trying to migrate to
  multiprocessing is because of the "spawn" method. It can be enabled on
  linux by using set_method("spawn"), and is the default method for
  MacOS, and the only method in Windows.

- Also, doing multiprocessing the right way is hard. See -
  https://docs.python.org/3/library/multiprocessing.html#programming-guidelines

- If you ever pursue "spawn" in the future, keep these in mind -
  https://docs.python.org/3/library/multiprocessing.html#the-spawn-and-forkserver-start-methods

v0.3.2: BUGFIX

Buffers closed in neovim weren't being disconnected from GhostText.
Fixed.

[HOTFIX] Fix for MacOS

See #50

Set multiprocessing.set_start_method("fork") before initializing
multiprocessing.Manager. Without this it will spawn an infinite number
of subprocesses on Apple M1.