ENH: Added istream and ostream operators for stl string when using old streams that do not provide them.

ENH: Adding SharedForward C header to help create forwarding executables on UNIX systems that configure the shared library runtime search path and then replace themselves with the real executable.  This is useful to create binary distributions that work from any extracted location even with shared libraries.

ENH: Re-implemented CollapseFullPath to not need to change directories.  Operation is now fully string based.

ENH: Added "ostringstream(const kwsys_stl::string& s)" and "void str(const kwsys_stl::string& s)" compatibility methods.

ENH: Adding kwsys::SystemTools::FileTimeCompare method to compare file modification times with the highest resolution possible on the file system.

ENH: Added try-compile KWSYS_STAT_HAS_ST_MTIM.  This tests whether struct stat has the extra st_mtim member that has high resolution times.

ENH: Initializing translation map using the PWD environment variable and getcwd functions to automatically translate logical paths involving the current working directory.  Also added the JoinPath method to aid users of the SplitPath method.

BUG: Need to include header <new> to use placement new syntax.  Really this should be fixed by replacing the stream buffer to set a new string instead of reconstructing the object, but this will require quite a bit of work to do portably.

BUG: add a test for a single char dir, and fix bug introduced in 1.53, but we still can not handle a space as the start of a directory name