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
Oh, DRY comments :-), when i was reviewing this, i had spent some time searching for what env this was required to, hence my proposition.

But it didn't take that long, so no worries then