Significant changes to cet_add_compiler_flags and
cet_remove_compiler_flags.

Both functions now support multiple and arbitrary languages.

_remove_compiler_flags() should actually work now.
cet_remove_compiler_flag() (note singular) has been removed. It is not
known to have been used thus far.

New file CetRegexEscape for cet_regex_escape. Optional extra argument
allows protection from interpolation when escaped result is passed to
functions and macros.
ICC does not support -Wno-unused-local-typedefs currently,
Tag for release with add/remove_compiler_flags changes.
added zsh support from Paul Russo
Correct logic error.
Split armoring functionality into a separate function.
Turn _rm_flag_trim_whitespace into a function to relieve need for armoring.
Improvements to CetTest macros.

Some macros turned into functions to reduce namespace pollution in
caller. This has the side effect of no longer requiring extra armoring
of \-escapes.

New argument REF to cet_test to allow comparison of standard output
against a known reference.

Use official CMakeParseArguments instead of CetParseArgs.
Bump version for release.
first attempt at adding PYTHONPATH support
Correct colon misplacement in argument spec.
remove premature change for shell support
Checkpoint (non-working) prior to cleanup.
Fully functional install_as_python(). See notes.
adding support for fwdir
fix typo
fixing fwdir, gdmldir, and pythonpath
cetbuildtools v3_11_00
Import bulk of simple_plugin functionality as basic_plugin.
Bump version to 3_12_00