Added notes for potential contributors.

I'm currently working on a way to make it sound nicer.
Added more contributor notes.
Add issue tracker link in header
change link texts in header.
Change style to Sandstone theme.

Also updated bootstrap, but that's less important.
header title is now shorter, for mobile devices.
Fix a couple punctuation errors
Did some restructuring of the index page
Merge pull request #5 from pharpend/contribute

Many improvements, mostly to the home page.