msvc 2019

[guruofquality]

Changes here:

Work in progress...

• switch to msvc 2019

• build qt5

• update boost

• update readme

• update wiki

• closes Add gr-sdrplay3 #83

• closes Add SoapyVOLKConverters to package #81

[guruofquality]

pygtk notes

• c:\build\gvsbuild>c:\Python39\python.exe build.py build -p x64 -c release --same-python --vs-ver 16 --enable-gi gtk3 pango cairo adwaita-icon-theme
• https://github.com/wingtk/gvsbuild
• Patch python gi __init__.py example python3.8 and above need stuff like this

import os
try: os.add_dll_directory("C:/gtk-build/gtk/x64/release/bin")
except: pass
os.environ['PATH'] = os.environ['PATH'] + ';' + "C:/gtk-build/gtk/x64/release/bin"