serenade_client.py: Create event loop instead of the (deprecated) default event loop

autoload/serenade.vim: Add serenade#RegisterUndo() utility function

README.md: Tweak wording.

serenade_client.py: increase file size limit to 1MB

serenade_client.py: add custom app icon

README.md: Update content links

Add SerenadeActive command

README.md: Add some more useful content including Tmux and Known Issues

serenade_client.py: increase maximum message size

Add gitignore

python3/serenade.py: make sure all log messages are prefixed with '[Serenade]'

README.md: a few tweaks here and there

Add some example voice commands to control Vim

Add configuration options to change the WebSocket address and enable/disable logging

Autostart vim-serenade when Vim starts