wxGTK30: updated to 3.0.5.1

3.0.5.1

This is a patch release updating the soname of the shared libraries for Unix/ELF systems which was forgotten in 3.0.5. Because of this, please use the source archives from this release if you're building wxWidgets shared libraries from source under these systems, but please refer to 3.0.5 files for all the rest, i.e. MSW binaries and the documentation.

For completeness, the only other changes compared to 3.0.5 are:
- Workaround for the problem with overflowing maximum command line length in MinGW builds not using configure.
- Fix for a problem with wxSpinCtrl in wxGTK

3.0.5

All:
- Support nullptr in wxPrintf() and other pseudo-vararg functions.
- Fix problem with wx-config installation and use under NetBSD (wiz).
- Avoid spurious errors on thread creation under NetBSD.

All (GUI):
- Improve stock items consistency and aesthetics (dhowland).
- Implement wxTextCtrl::HitTest() for single line controls.
- Improve wxSVGFileDC to support more of wxDC API (Maarten Bent).

wxMSW:
- Fix handling of AUX2 mouse button events (Trylz).
- Honour alignment flags for multiline buttons using custom colours too.
- Fix crash when using wxCHMHelpController() in 64 bit builds (Xlord2).

wxGTK:
- Fix position of popup menus shown in wxListCtrl.
- Fix not showing wxInfoBar with GTK+ 3 < 3.22.29.
- Potentially incompatible change: wxDataViewModel::Cleared() now works as
  documented cross-platform.  Previously on wxGTK it just emptied the model
  rather than triggering a reload of the model.  If you are working around the
  broken behaviour with wxGTK-specific code in your application you should
  check that your application works correctly with this change.
- Return appropriate values for some previously hard-coded system colours.

(adam)