Update to the latest version of ByteArrayClass from the QtScript examples.
Guard Qt >=4.7.0 logic with ifdef.
Change dropAccept and dropAcceptChild to accept QObject sources instead of QWidget (needed for qt5 migration).
Fix one more use of FALSE.
Remove double-include.
Explicitly include <QtConcurrent> due to qt5 modularization.
Fix SongDownloader formatting.
Special-case some qt4 / qt5 incompatibilities.
Add util/compatibility.h, a file for compatibility helpers to allow us to support Qt4 and Qt5 concurrently.
Add QtWidgets and QtConcurrent to list of valid modules.
At Qt5 support to the Qt dependence (enabled via a 'qt5' scons parameter). Also simplify the way we enable Qt modules (which will likely cause some build breakage on some platforms).
fixes "['QtXmlPatterns'] are not Qt4 modules.", a missing comma
tried to compile wit Qt5 modules, but fails with compile errors.
Merge pull request #88 from daschuer/qt5

Merge Linux Qt5 updates from daschuer@.
Update Qt4 SCons tool from upstream and add the Qt5 SCons tool.
Use pre-computed boolean flags.
Add qt5 SCons tool.
Wrap qt5-enabled check in a helper.
Use the right qrc based on the Qt version.
Check for Qt5Core >= 5.0 on Linux when qt5 is enabled.