Correctly serialize separator field

Whoops!

Enable reloading config while running

Use SIGUSR1 or the helper command `swaybar-commander reload` to trigger
a config reload.

Create update chan as part of block

Fix typo

Replace deprecated function calls

Update sample block to correctly handle volume=0

Print 0 instead of nothing.

Update samples to what I currently use

Re-word contributing section

Add link to project home page

Correctly label as swaybar status command

Add sample blocks

Link to git repo, not project home

Allow an update requester command for each block

Add helper command to easily request block updates

Ignore build artifacts

Allow triggering block updates with signals

Add doc comments

Change 'refresh' to 'update'

Create initial basic version

- Run blocks at a specified interval, and only actually send updates to
  swaybar as needed.

- Load configuration from a TOML config file.