First release candidate

This is a release candidate for squirssi v1.

Getting started with this rc:

1. Download the version suitable for your platform, along with config.toml.dist.
2. Place the squirssi executable where convenient.
3. Move config.toml.dist to ~/.squirssi/config.toml and edit the contents accordingly.
4. Run the squirssi executable!

Commands in squirssi are prefixed with /. Type /help for a list of commands.