added utf8 encoding line to python templates

python breaks if it encounters special characters
in files without specified encoding.
Which is especially funny if you've got umlauts
in your name.
Created atsc_rx.py and removed obsolete scripts

Several bug fixes and speedups rolled into one ATSC
decoder script. The old method included separately
launched scripts linked with named pipes, this was
tedious and slowed down decoding, so I have moved
their functionality into one flowgraph.
grc: checks for virtual/pad source/sink and ignores them for affinity and buffer size fields.
Merge remote-tracking branch 'mmueller/modtool_py_utf8' into maint
Merge branch 'maint'
wxgui: Prevent a crash at displaying the tooltip when the graph is not yet populated
Merge branch 'maint'
Merge remote-tracking branch 'glneo/atscfixup'
build: require Python v2 for build configuration
Merge branch 'maint'
runtime: bug fix for asynch messages not getting delivered correctly to the queue when a handler is not defined (queue is accessed from the work function only)