ENH: Removing special termination pipe from Windows implementation.  It does not need it because WaitForMultipleObjects can wait with a timeout for the process to terminate.  This is not the case in UNIX because waitpid has no timeout, so we need the termination pipe there.

ENH: Added special termination pipe to allow timeout to work for processes that close their output pipes.

ENH: Error messages from the forwarding executable are now read completely even if they are reported in multiple blocks.

BUG: When a child fails to exec, we need to read the entire error message, not just the first block.

BUG: Removed CloseHandle in case of error in DuplicateHandle.  According to documentation, DuplicateHandle will close the source handle regardless of error condition.

ENH: add the unix makefile generator as an option from the windows GUI, this builds with mingw, cygwin, and combinations of make cl, bcc32

ENH: Added use of KWSYS_HEADER macro in c and cxx files to include kwsys headers through their configured namespace.

ENH: Add optional argument to GetLineFromStream which can let the caller know whether there was a new line character at the end of the line that was just read