add autoloads for .vim extensions and rc files

Fixes #1
Merge pull request #2 from holomorph/master

autoloads
change to unix line feeds
Merge pull request #3 from holomorph/lf

change to unix line feeds
use backquote and markers
use prog-mode if possible
add a couple more variable types
separate `no' variables from the rest

* nuke the existing regex and use regexp-opt
* lists created by hacking vim's options.txt help text
improve function regex
redo ex commands
only consider line comments

* comment and string behaviour is rather broken, so let's keep it simple
  for now
* separate faces for the comment and its delimiter
redo built-in functions
add mode-specific faces

* generally good to expose configurable faces
* no need to highlight fun[ction] contextually
* s/Variables/Options/ where appropriate
add some sections
catch more variables
add rudimentary imenu and expression nav

* navigate function definitions
* imenu catches function and variable definitions at BOL
* use setq-local
* use a syntax table
* mode customization group
clean up the header
add self to header

catch some extra/missing keywords
Merge pull request #4 from holomorph/rewrite

Rewrite
Correct mistake in vimrc-mode-syntax-table