Update README.md

Use https instead of ssh for checkout instructions so it works for people without commit rights.
Add coffeescript ctags support
Add vim-emblem
Replace .rvmrc with .ruby-version and .ruby-gemset
There are no ruby files in dotmatrix
Remove unused map
Bring back Y vim map
Better mappings for splitjoin.vim

gJ and gK (mnemonic is the directionality of up and down)

For more information, within VIM:

    :help splitjoin
Merge remote-tracking branch 'hashrocket/master'

* hashrocket/master:
  Better mappings for splitjoin.vim
  Bring back Y vim map
  Remove unused map
  There are no ruby files in dotmatrix
  Replace .rvmrc with .ruby-version and .ruby-gemset
  Add vim-emblem
  Add coffeescript ctags support
  Update README.md

Conflicts:
	bin/vimbundles.sh