Make CommandT::VIM::Window a module
Make CommandT::VIM::Window a module

As noted in the previous commit, this class had no instance methods and
it was meaningless to instantiate an instance of it.

If it's just serving as a namespaced container for methods, it should be
a module. This commit makes it so.

yrro/command-t,1234-/command-t,besarthoxhaj/command-t,vrkansagara/command-t,lencioni/command-t,mtimkovich/command-t,wincent/command-t,1234-/command-t,vrkansagara/command-t,simichaels/dotfiles,supriyantomaftuh/command-t,wincent/command-t,simichaels/dotfiles,mtimkovich/command-t,yrro/command-t,lencioni/command-t,supriyantomaftuh/command-t,besarthoxhaj/command-t,wincent/command-t