Remove duplicate ruby snippets

The snippets/ruby.snippets file defines two snippets
that already exist in the vim bundle.  When you try
to use either `let` or `its`, vim must ask you which
of the identical snippets you wish to use.

Removing the duplicates means that your snippets are
actually faster than typing the expanded text out
manually.
Add ,ld command to make a let(:double)

Want to easily make a named double for your rspec tests?
Just write your desired variable on a line, then with the
cursor over the variable, press `,ld`.

You can easily convert:

    local_vari*able_foo

to:

    let(:local_variable_foo) { double(:local_variable_foo*) }

where `*` represents your cursor.

Notice that you end up in a great position to add
key/value pairs!
Merge pull request #37 from mkenyon/fix-vim-ruby-snippet

Remove duplicate ruby snippets
Merge pull request #36 from mkenyon/add-let-double

Add ,ld command to make a let(:double)
Move implementation of local_make_let to own file
Turn off airline’s buffer tabline
Set airline’s theme to tomorrow so it matches
Merge branch 'master' of https://github.com/pivotalcommon/vim-config