Omit MacVim cask install

Due to problems with indexing and launching from the terminal,
I'm avoiding installing MacVim via Cask for now. I'm looking
at installing it differently or fixing the issues the prevent
those things from working correctly.
Install MacVim via cask

Continue installing MacVim via cask, as the problem is with
Spotlight not indexing through symlinks. This is suboptimal, but
an alias can be added in /Applications to work around it for now.