Vim processing.

This is an extension of vim script #2115. It started simply as an easy git repo
to bundle and use with pathogen, but has grown as I use processing more.

I have made two sets of modifications so far:

1) Documentation is now browsable locally or on the web. If you set the
variable processing_doc_style to "local" it will use a local copy of the
processing docs (and requires you to set the variable processing_doc_path to
point to the root of the documents). If you set processing_doc_style to "web"
it will point your browser at the processing site when you use attempt to use
the documentation hookup.  (normal mode K)

2) For OSX users, I have created a applescript to tell processing to run the
script in question. For this to properly work, Processing must already be
running, and it works best if the "use external editor" preference is selected.
Simply pressing F5 will cause this applescript to select the processing window
corresponding to the pde we are editing, and presss the 'run' button. This
is still pretty fragile, but works well enough to significantly increase the
effectiveness of my workflow. If you know of better ways, please share!