With strings, we don't need to care about passing in a length, since it internally stores it. So now, we don't even need a length parameter for these functions anymore as well.
This also kills off some sprintf_s calls.
We need to explicitly round when converting colors from float to uint
because multiplying a normalized float by 255 might not result in a whole
number. (The exact result here may vary depending on your
drivers/hardware.)
Ideally, we shouldn't be using floating point here, but fixing that is a
much more complicated patch.
Fixes gxtest TEV tests using Intel HD 4000.
