Add shell autocompletions

[kke]

Shell autocompletions

• bash-completion.sh completion config
• mortar install-completions [--remove] subcommand that tries to automatically [un]install to known default locations
• gem post-install message and README update

[jnummelin]

Maybe add also instructions how users can get it to work?

[kke]

It would be possible to write a lib/rubygems_plugin.rb that would get installed when using rake install (which nobody does) and/or a Makefile that would do it.

Or spec.post_install_message = "To install bash-completions, etcetc"

Also maybe we should make a brew formula.

[kke]

I wrote an installer. I put it in lib/mortar/bash_completion_installer.rb that gets required from bin/mortar if you use mortar install-completions.

Of course it could be a regular subcommand or just instructions how to install manually.

[jnummelin]

I'd rather see it as a regular sub-command.