Add mr's vcsh lib to docs

* Make include more resilient (Thanks to Thomas Koch)
* Fix emphasis issues with underscores in variable names in MarkDown

Thanks to Brain May for pointing this out.

fixes #22

Thanks to Brian May for reporting this.

fix #22

Thanks to David Bremner for reporting this

People arriving via http://onethingwell.org/post/14218384411/vcsh
should be able to find us..

github:
fixes #6

for github:
fix #9

Thanks to Gernot Schulz for writing most of the new content. It somewhat overlaps with INSTALL, but more docs are better either way.