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.
Merge remote-tracking branch 'mmueller/modtool_py_utf8' into maint
wxgui: Prevent a crash at displaying the tooltip when the graph is not yet populated
build: require Python v2 for build configuration
runtime: fix asynch messages delivery when handler not defined
blocks: expose set_period callback for blocks.message_strobe in GRC
build: fix for finding and handling ICE 3.5 or 3.4