firefox: Bump to 31.0. The make was failing on some js and could not fin...

...d/determine

a fix, disabling shared js skirted around this issue.

Added some if/then logic should qt4 be installed.

Commented out the sqlite in DEPENDS. AFAIK that is still valid.

Re-enabled cairo, compiled fine and haven't found any issues.

Only one thing I have found and this existed in the 29 version that was in moonbase. Firefox would silently crash. The most reliable way for me to do this; login my gmail account and just wait a hand full or so seconds, boom. Forgot to bookmark them but a preliminary search appears to indicate a problem with gtk2 and zero width pixels. Apparently this is not an issue with firefox-bin?