VideoCore: Unify interface to OpenGL and SW rasterizers

This removes explicit checks sprinkled all over the codebase to instead
just have the SW rasterizer expose an implementation with no-ops for
most operations.

src/video_core/CMakeLists.txt

@@ -11,8 +11,10 @@ set(SRCS
             pica.cpp
             primitive_assembly.cpp
             rasterizer.cpp
+            renderer_base.cpp
             shader/shader.cpp
             shader/shader_interpreter.cpp
+            swrasterizer.cpp
             utils.cpp
             video_core.cpp
             )
@@ -30,13 +32,14 @@ set(HEADERS
             clipper.h
             command_processor.h
             gpu_debugger.h
-            hwrasterizer_base.h
             pica.h
             primitive_assembly.h
             rasterizer.h
+            rasterizer_interface.h
             renderer_base.h
             shader/shader.h
             shader/shader_interpreter.h
+            swrasterizer.h
             utils.h
             video_core.h
             )