BGE Python API

- More verbose error messages.
- BL_Shader wasnt setting error messages on some errors
- FilterNormal depth attribute was checking for float which is bad because scripts often expect ints assigned to float attributes.
- Added a check to PyVecTo for a tuple rather then always using a generic python sequence. On my system this is over 2x faster with an optmized build.

source/gameengine/GameLogic/SCA_MouseSensor.cpp

@@ -279,7 +279,7 @@ KX_PYMETHODDEF_DOC_O(SCA_MouseSensor, getButtonStatus,
 		
 		if ((button < SCA_IInputDevice::KX_LEFTMOUSE)
 			|| (button > SCA_IInputDevice::KX_RIGHTMOUSE)){
-			PyErr_SetString(PyExc_ValueError, "invalid button specified!");
+			PyErr_SetString(PyExc_ValueError, "sensor.getButtonStatus(int): Mouse Sensor, invalid button specified!");
 			return NULL;
 		}