Cygwin: updates to wire in profiler, gmondump

Cygwin: updates to wire in profiler, gmondump

These are updates to wire into the build tree the new tools profiler and
gmondump, and to supply documentation for the tools.

The documentation for profiler and ssp now mention each other but do not
discuss their similarities or differences.  That will be handled in a
future update to the "Profiling Cygwin Programs" section of the Cygwin
User's Guide, to be supplied.