recipes for Qt5/sip/PyQt5 stack on windows, linux, osx

compiles using MSVC express 2010 for Qt5, MSVC 2008 for sip and pyqt5. Uses precompiled ICU binaries (build and runtime requirement for Qt5 on windows), and uses precompiled jom executable to perform the build in parallel.

Would have liked to build Qt5 with MSVC 2008, but it was not successful due to a known bug.