Internals: Create graph clone methods.
Add --report-unoptflat, bug611.

Signed-off-by: Wilson Snyder <wsnyder@wsnyder.org>
IEEE 1800-2012 is now the default language.  This adds 4 new keywords and updates the svdpi.h and vpi_user.h header files.
Merge branch 'master' into verilog-short-circuit