Add UltiSnips

UltiSnips seems to work better than snipmate. We'll see how it works.

Remap ultisnips default keys to not use Tab.

<C-r><Tab> was the old way and since <C-j> replaces <Tab>, use that.
Using tab regularly should now be faster since nothing is mapping it.
add a submodule with my snippets

setup for ultisnips
Remove snipmate

I'm switching to ultisnips. One day the two may merge, which would make
ultisnips better. But it doesn't have some of the bugs that annoy me, so
it's good enough (even without the great completion menu).
Add orgmode

Orgmode requires python, but seems to be a superior (and simpler)
orgmode plugin. (It doesn't lose syntax highlighting when the window is
closed nor does it add a menu.)
Remove VimOrganizer and calendar

VimOrganizer has lots of features that I don't know about or use, so I'm
swapping it for vim-orgmode (which depends on python, but at first
glance doesn't have the same problems).

I only installed calendar for VimOrganizer. I don't need a calendar, so
dump it too.