Build: Fix various typos

Thanks @jamesgpearce, @imyousuf
Ref dc4b914a05e1e6dbf13f916897b5d6a472ea0380
CSS: Fix get upper case alpha opacity in IE8

Fixes gh-1705
Closes gh-1704
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-1836
Fixes gh-1701
Refs gh-1815
Refs gh-1820