[effects] Check for LimitedNPOT
Review Request #126966 - Created Feb. 2, 2016 and submitted
Effects which require mipmaps need to check for LimitedNPOT and disable the functionality if it's not available. Ideally they could also check whether the texture they operate on is a power of two, but that's a little overkill for the rather uncommon setup.
the commit message is wrong, needs to be disabled if only LimitedNPOT is supported (the flags name is actually confusing, because full usually implies limited support, maybe we would want to alias OnlyLimitedNPOT?)