.osx: Suppress error messages when running `~/.osx` twice

Closes #266.
.aliases: Improve `ips`

Ref. #268 and #269.
Make `.cask` executable
.osx: Minimize windows into their application’s icon

Closes #271.
init: Add iTerm colors

Closes #274.
init: Install Sublime Text settings

Closes #275.
.osx: Rename computer name