Previously Visual C++ users were forced to link CRT statically,
i.e. use /MT flag whenever they want to use the static library.
Linker have an error if user tries to link a /MT static library
to a /MD executable.
This commit defaults the build to statically link with CRT, but
may be turned off if needed.
- Only require JRE
- Support out of tree build from antlr repostitory
- Support Superproject build with ExternalAntlr4Cpp cmake module
ExternalAntlr4Cpp module has quickstart documentation for people to be
able to start working quicly with antlr4cpp from the base demo sources
see source file for example.