Fix brew install URL

Fixes #150
Merge pull request #151 from ram-nadella/patch-1

Fix brew install URL
Add tmux.conf.local
Update phinze/cask to caskroom/cask

It triggered this warning if brew cask had already been upgraded
to caskroom/cask and we ran rake:

> Warning: Could not tap phinze/homebrew-cask/brew-cask over
> caskroom/homebrew-cask/brew-cask
Merge pull request #156 from slam/tmux_local

Add tmux.conf.local
Don't recursively map all the time

If users remap keys, the behaviour of the things set up in vimrc may change.

An example of this is the common remapping to switch `;` and `:`, which will
cause all of the keyboard shortcuts involving `:` to fail. Switching the *map
statements to their *noremap counterparts fixes this problem, by using the
original meanings.
Merge pull request #158 from ElliottH/mapping

Don't recursively map all the time
Don't copy the contents of an overwritten selection.
Document select-paste vim config.
Clarify the visual selection overwrite docs.
Merge pull request #161 from square/donovan/dont-copy-replaced-selections

Don't copy the contents of an overwritten selection.
Merge pull request #155 from slam/caskroom

Update phinze/cask to caskroom/cask
Clarify our position around adding new features to maximum-awesome.
upstream added tmux.conf.local loading. merge to upstream.