[hpsdr] Update to Gnuradio Hermes/Metis for GRC3.7

[Tom McDermott]

Gnuradio has released version 3.7.  Upgrading has a few challenges.
You must run a script to remove all old versions of Gnuradio before
running the 'wget' installation from the Gnuradio webpage to install the
latest (3.7). Instructions and that Gnuradio_remove script are in the
TAPR SVN repository in the GRC3.7 branch. Failure to remove the
old version(s) will break all Gnuradio Bandpass filters, maybe some
others as well.

After installing GRC3.7 and confirming it's working, then the new software
for Hermes/Metis must be installed from the GRC3.7 branch in the
TAPR SVN. The code, directories, etc. all changed a bit from GRC3.6
to GRC3.7. The installation instructions however remain the same.

The grc-applications for Hermes/Metis also change due to modifications of
some GRC3.7 blocks. The directory in the GRC3.7 branch has the updated
demo applications.

Some of the blocks in GRC3.6 dissappeared, replaced by slightly different
blocks in GRC3.7.  If you have a design that used a depricated old block,
it will not be there when you open your application in GRC3.7. You'll
need to remember what they were and hunt down the replacements.
I recommend you open and print all your applications prior to removing
version 3.6 so you'll remember what to do.

The QT FFT GUI changed in GRC3.7.  It no longer supports adding an
offset to the frequency display (which was most convenient). Many of
the hooks in the GUI are still there to do it, so we can hope it's a
GRC3.7 bug rather than a depricated feature.

OSMOSDR does not seem to have been updated yet to GRC3.7. It fails
to install properly, but that doesn't affect OpenHPSDR at all.

I recommend doing a check-out from the SVN because it puts all the
right files in the right directories on your linux machine to do the build
and install of the Hermes/Metis modules.

http://svn.tapr.org/repos_sdr_hpsdr/trunk/N5EG/GRC3.7

-- Tom, N5EG