Support view-bb, view-bbs
Support view-loop
gcc -fplugin= -fplugin-arg-vcg_plugin-cgraph foo.c

Dump the cgraph.
support -fplugin-arg-vcg_plugin-cgraph-callee
support -fplugin-arg-vcg_plugin-cgraph-caller
Support more options
More examples; Fine tune graphs; Update
bug fix; version 1.8