add a link to nightly windows builds
fix a bug in our mainwindow ui design

it wasn't possible to add new tab pages from the qt designer
added a QWidget container with a vertical layout as this is
done also if you create a new empty mainwindow
add qcustomplot qt plotting widget 1.2.1
plotting: add a simple mechanism to visualize data

added a plotting dock, where you can select x and y axis
and it will draw a chart out of it
better visualize the log from the execute sql tab
plot: wrong date format
Update qmake files

As promised, here is me updating the qmake project files in order to
allow building the new version with qmake instead of cmake.