Reorder path.

Dotfiles defines $PATH in a place that breaks the path order for some
shells. I always want ./bin to be in the front of the path order.
Use bigger font in MacVim by default.
Move OSX github.app config updates to local dotfile.
Fix initial fontsize in macvim.
Revert zsh 'rspec' function to upstream.

I don't use Zeus, so I'm wondering if this little thing slows down tests
at all. Had previously modified this function to override Thoughtbot's
rspec wrapper because of an issue with Spring 1.1.0 where none of my
specs were run unless a specific spec location was declared. Problem
seems to be gone in Spring 1.1.1 either because of changes on my machine
or a code fix, I really don't care to investigate further given how much
time was already wasted here.
Use hub over git for 'g' function.