Fix deletion of delimiters on their own lines

Closes #19.
Remove documentation of LaTeX expansion

It's dumb, but I can't bring myself to yank it out entirely just yet.
Add leading space replacement
Add : replacement

Both Ruby and Clojure use :keywords, so I'm considering this general
enough to make a default.
Add a lisp function call replacement

Not sure how useful this is but we'll sneak it in undocumented.
surround.vim 2.0

* Fix vs with selection=exclusive.
* Remove `unnamedplus' from clipboard in addition to `unnamed'.
* Kill vs.
* Bump to Vim 7.
* Add support for repeating ys commands.
* Add support for repeating tags.
* Don't save deleted surrounding in unnamed register.
* Fix deletion of delimiters on their own lines.
Default to automatic indenting

Only one way to find out if this is actually a good idea.
Support to disable mappings only for insert mode

If disable mappings only in normal mode.
let g:surround_no_insert_mappings = 1
Merge git://github.com/tpope/vim-surround into HEAD