Added SM2 instancing shader and got it nearly compiling.

DX9 bytecode changes:
-Partial support for relative addressing
-Fix conversion of pre-SM4 sincos to SM4 sincos.
-MOVA now using floor instead of round because round is not available on
all GLSL versions. This change may need revisiting, forcing a min
requirement of GLSL 130/GLSL ES 300 to support this instruction.
-Swizzle for src operands
-Write mask for dest operands.
Add GLSL 4.40 as a target language
tests\vs2\VS_ShaderInstancing.o now compiles

Add terminating RET to end of dx9 shaders.
Use OPERAND_4_COMPONENT_SELECT_1_MODE for replicated swizzles -
previously could end up with code like Temp2.x = Temp1.zzzz +
Temp1.yyyy;