Blender Git Loki

Node inputs now have a 'value type' to specify how input connections are treated.

VALUE_CONSTANT inputs can not have connections, their values are known at compile time.
bvm stores these values directly in the instruction list.

VALUE_VARIABLE inputs store values at evaluation time. bvm stores a stack index for them
which is used to load and store from/to the evaluation stack.

VALUE_FUNCTION inputs are passed to kernels to be called internally when needed.
bvm stores an instruction index and allows a jump to this instruction (TODO).