Fixup crashes and major issues created by porting
to QT5. These have included;
* Fix CP plot log scale
* AllPlot axes and tooltip
* DBAccess prepare/bind bug
* LTMSettings crash
* LTMWindow zoomer/picker crash
* LTMPlot axes hack
There are still issues remaining but we can start
working through them at leisure -- the product now
builds and runs.
Upgrade to QWT 6.0.1, but still uses a locally patched copy
since support for 8 axes has not been included, despite it
being a relatively simple patch.
Fixes#634.
Fixes#567.