SCS is unfortunately a fragment program only instruction. If we have the NV
extensions we can use SIN and COS. Otherwise we have to approximate sine and
cosine with a taylor series. Luckily we're provided with the necessary
constants by the application.

TMP_POS is only used in vertex shaders, declare it in the vshader
specific code. The sRGB constants are only used by pixel shaders, so
move them to the ps specific code, and avoid reading the stateblock.

DSY is not that easy because we have to deal with the inverted coordinate
system in onscreen(!) rendering - see GLSL dsy.

d3d9/tests: Add simple test to show that QualityLevels is not zero, when we call CheckDeviceMultiSampleType with D3DMULTISAMPLE_NONE.

In D3D10 shaders input/output semantics are strings rather than predefined
types. Unfortunately, the code in vshader_get_input() can be performance
critical, depending on application behaviour. Since vshader_get_input() is
only relevant for d3d9 shaders anyway, just store the usage and usage_idx for
these shaders.