runtime: Fixed libgnuradio-pmt MSVC incompatibility errors
wxgui: Fixes to solve issues using GL sinks on OS X
plotter/plotter_base.py: Create explicit OpenGL context, check if window is shown before realising context & only create PaintDC is paint triggered by WM message (OS paint event)
Added SetSizeHints to WX sink windows so sizing occurs correctly
pmt: added DLL resource file for MSVC
Merge branch 'maint'
Merge branch 'master' into next
Merge remote-tracking branch 'ncorgan/pmt_rc' into next