It adds new type of flexibility, where just entered text can be
dynamically modified if some conditions are satisfied (e.g. dynamically
add line wraps).
The python module is now pulled in autoload/UltiSnips.vim. This means
that parsing of the .vimrc will only map the keys and set some options -
very cheap.
Unfortunately, the autocommands set up in plugin/UltiSnips.vim pulls in
the python code basically immediately still.
