Added generation flag -g2009 which enables support for 1800-2009
constructs. Added related support such as "1800-2009" in the
`begin_keywords directive.
Keeps 2005 as the default generation for now.
Removed the -gsytem-verilog flag and folded the 1800-2005 stuff into
1800-2009. The rationale behind this is we have so little of
1800-2005 actually implemented that it does not make sense to
distinguish between 1800-2005 and 1800-2009 SystemVerilog extensions,
so we just count them all as the new 1800-2009 Verilog language.
Try to put all the version stamps into common version_base.h
and version_stamp.h header files. All the source programs then
get their version from these header files.
Also handle the version stamps in the man pages by using the
version_*.h header file contents to edit the version strings
in the man page title bar markers.