Replace t (twitter client) with Timetrap in `install/gems`
Replace t (twitter client) with Timetrap in `install/gems`

These two gems are incompatible because they both include an executable
named `t`. Since the t twitter client is not currently being used and
timetrap is preferred, replace t with Timetrap.

alphabetum/dotfiles,alphabetum/dotfiles,alphabetum/dotfiles,alphabetum/dotfiles