mapserver: pass --with-cairo to configure

Configure does not automatically enable cairo bindings
(for svg/pdf support)
macvim: Now builds with brewed python 2.x

The python3 option has been removed because enabling it
made the MacVim GUI disappear when `:python3` is executed.

Further, using Python 3.x seems to disable the 2.x bindings.

Now tested to work with powerline.