Change file extensions to .h/.cc

CMakeLists.txt

src/common/manager.cc

src/common/manager.h

src/common/memory.h

src/cpu/ee/cop0.h

src/cpu/ee/ee.cc

src/cpu/ee/ee.h

src/cpu/iop/cop0.h

src/cpu/iop/iop.cc

src/cpu/iop/iop.h

src/main.cc