Feb. 2020

By default, OP25 builds for python2 and gnuradio3.7.

Rather than branching the repo source tree and until such time as 
gnuradio3.8 should become standard, it was decided to distribute 
the necessary mods to build OP25 for gnuradio3.8 / python3 in
the form of a patch (in file gr3.8.patch).

To apply 
# first, if necessary "sudo make uninstall" from your build dir
#       (if op25 already installed)
# then, cd to the top level op25 directory
cat gr3.8.patch | patch -p1
# finally, run "install.sh" as usual

NOTE: This patch only affects the cmake (build) process; the 
python apps (.py files) have been rewritten to be compatible with
either version (2 or 3) of python.  It's possible there may be
leftover bugs from that process  - please report if so.