Version 1.9

Add new handlers:
* Ruby (ri)
* bash's help
* GNU info (smart support for: awk, make, m4, automake)
* LaTeX (help_custom)
Perldoc and Ruby support ANSI (need Improved AnsiEsc plugin).
Improve Python support.
Added support for multiple documentation providers per filetype.
Added option to search for the word which is being looked up in the buffer.
Make :h work.
Renamed [Scratch] to [DocN].
Add b:topic.
Added {{winwidth}} support in h.cmd (man and perldoc already using it).
Version 1.9@1: vimball