Sigh - restore compatibility with Qt < 5.14 (I hope)

Qt6 compatibility

Fix some compiler warnings

Add importString/loadString functions; fix some memory leaks; update to avoid deprecated APIs; tidy in a few places

Avoid compiler warning for deprecated API we can't readily replace

Fix compiler warning

Catch exceptions by reference

Fix compiler warnings

Remove staticlib, restore dynamic libs!

Added tag v0.9.1 for changeset 768fb9b05355

Update version

Update to C++11, and make a fix to throw-from-dtor logic (i.e. don't do it) along with a few other compile and warning fixes.

Meta + config

Rename DEBUG to DQ_DEBUG (as DEBUG is often used as a flag). Also fix some warnings.

build fixes

win32 target name

Actually, I think we have to do percent encoding ourselves (QUrls converted to strings are de-encoded)

Add a note about percent-encoding spaces etc

Make tests compatible with Qt4

Ah, no, we did still need one retrofix for Qt4