ceil @input-height-large calculation

Created by: yokomizor

This is the current @input-height-large calculation:

@input-height-large: (floor(@font-size-large * @line-height-large) + (@padding-large-vertical * 2) + 2);

or

@input-height-large: (floor(18 * 1.33) + (10 * 2) + 2);

I've noticed that: 18 * 1.31 = 23.58 18 * 1.3 = 23.4

I've been looking for #10936 (closed) and I've noticed that when line-height of .input-group-addon is 1.30 it looks fine, but when line-height is 1.31 it breaks on FF 24 OSX.

Maybe FF rounds up line-height, so I think it is safer to round this value up with ceil().

I hope this fix #10936 (closed) and #10482 (closed). I've tested on FF 24 OSX and it works fine.