storm-1189: remove more of the code for classic clouds

indra/newview/CMakeLists.txt

indra/newview/llcloud.cpp

indra/newview/llcloud.h

indra/newview/lldrawable.cpp

indra/newview/lldrawpool.cpp

indra/newview/lldrawpoolalpha.cpp

indra/newview/lldrawpoolclouds.cpp

indra/newview/lldrawpoolclouds.h

indra/newview/llspatialpartition.cpp

indra/newview/llspatialpartition.h

indra/newview/llstartup.cpp

indra/newview/llviewerobject.cpp

indra/newview/llviewerobject.h

indra/newview/llviewerobjectlist.cpp

indra/newview/llviewerregion.cpp

indra/newview/llviewerregion.h

indra/newview/llvoclouds.cpp

indra/newview/llvoclouds.h

indra/newview/llworld.cpp