Build: Put "jQuery Compat" in banners in built files
Build: Update license

(cherry-picked from 4f776e5ff91c48891f02d1ca3ba31132477d3972)

Closes gh-1587
Build: Point to files from the compat branch, not master
WIP: Misc: Drop support for older browsers; update support comments

That includes IE<8, Opera 12.x, Firefox<29, Safari<6.0 and some hacks
for old Blackberry.

Fixes gh-1701
Refs gh-1815