ENH: Do kwsys testing as part of cmake testing, command line arguments are not experimental and add simple test for systemtools

ENH: Adding SGI hash_map and hash_set implementation ported from STL to KWSys.  This also adds try-compiles for KWSYS_STL_HAS_ALLOCATOR_REBIND, KWSYS_CXX_HAS_FULL_SPECIALIZATION, KWSYS_CXX_HAS_MEMBER_TEMPLATES, and KWSYS_CXX_HAS_NULL_TEMPLATE_ARGS.

ENH: Removing extra 64-bit search paths.  They are now constructed automatically from the paths listed.

BUG: Fix rule name for subdirectory traversal to use relative paths.  This was broken by the recent subdirectory changes.

BUG: Avoid duplicate definition by using cmsys_STL_STRING_NEQ_CHAR_DEFINED and cmsys_STL_STRING_NO_NEQ_CHAR.

ENH: Added proper namespaced version of KWSYS_STL_STRING_ISTREAM_DEFINED, KWSYS_STL_STRING_OSTREAM_DEFINED, and _STL_STRING_NEQ_CHAR_DEFINED macros.