More of a call-to-action voice for forks and pull requests on NCIP

Between

 "We are strongly encouraging forks and pull requests."

and

 "We strongly encourage forks and pull requests."

the former is tentative, the latter a more definitive call to arms.
Merge pull request #226 from randomecho/ncip-encourageable-forks

NCIP post - More of a call-to-action voice for forks and pull requests
Resize the logo to the size it's being used.

This fixes the problem with old browsers that don't support the `background-size` property.
Switch to `row-fluid`.

This fixes issues with older browsers like IE8.
Switch to using an `img` for the logo.

Also fix the navbar elements overlapping in 754px-767px width.