Improve zsh completion

[itiut]

This includes 3 improvements for zsh completion.

• Enable function autoloading.

  When gibo-completions.zsh is copied as _gibo into the directory contained in $fpath, running source path/to/gibo-completion.zsh becomes unnecessary.

• Improve performance of listing boilerplate files by replacing find command with globbing.

  find command with -exec basename argument takes several hundreds of milliseconds but globbing doesn't take so much time.

   $/usr/bin/time find ~/.gitignore-boilerplates -name "*.gitignore" -exec basename \{\} .gitignore \; > /dev/null
       0.47 real         0.15 user         0.20 sys
   
   $/usr/bin/time echo ~/.gitignore-boilerplates/**/*.gitignore(:r:t) > /dev/null
       0.00 real         0.00 user         0.00 sys
  

• Complete options, too.

   $ gibo -[press TAB]
   --help     -h  -- Display this help text
   --list     -l  -- List available boilerplates
   --upgrade  -u  -- Upgrade list of available boilerplates
   --version  -v  -- Display current script version
  

[simonwhitaker]

Cooooool! Thanks!

[itiut]

Thanks! Would you bump up the version to 1.0.5 for installation with Homebrew?

[simonwhitaker]

Done