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
Yeah, I don't understand it either. I get this on Chrome & Firefox (& I suppose everything) when this line is removed: 
![screen shot 2014-11-08 at 18 10 00](https://cloud.githubusercontent.com/assets/1758366/4964886/a3c2258c-6772-11e4-8de4-e48e97972b42.png)