qtgui: fixes some bugs between qwt 5 and 6, some reorg.
ctrlport: only convert strings to bytes for probe2_b data.
grc: fixes module misnaming from 3.6 to 3.7.

Patch supplied by G33KatWork via github.
Merge branch 'maint'
blocks: interleaved_char_to_complex grc xml fix
digital: updated narrowband examples with --lo-offset and --clock-source options
digital: fixed ofdm benchmark_tx. flowgraph was closing down before tx queue was empty
fft: fix XML import for logpwrfft block
cmake: force detection to Python 2.x only
runtime: fix hier_block2 disconnect_all()
Merge branch 'maint'
utils: Fixes grcc to exit with an error code in case of a compilation error.
Merge branch 'maint'
grc: Sorts the block tree column at start-up.
blocks: adding a complex VCO block.
filter: added optional second input that dynamically adjusts resampling rate.
runtime: Fixed runtime SWIG linker error

* gnuradio_runtime_EXPORTS is not defined for SWIG builds by default, so this fix manually sets it for the runtime_swig build
Merge remote-tracking branch 'ncorgan/runtime_swig_fix' into maint
Merge branch 'maint'
build: installing all cmake files into lib/cmake/gnuradio directory.