rasterizer: Rename from overdrawanalyzer.cpp

This allows us to expose more rasterizer like functionality without the
name becoming confusing.

Author: zeux

CMakeLists.txt

@@ -28,10 +28,10 @@ set(SOURCES
     src/indexanalyzer.cpp
     src/indexcodec.cpp
     src/indexgenerator.cpp
-    src/overdrawanalyzer.cpp
     src/overdrawoptimizer.cpp
     src/partition.cpp
     src/quantization.cpp
+    src/rasterizer.cpp
     src/simplifier.cpp
     src/spatialorder.cpp
     src/stripifier.cpp