High/Low DPI Adapting

The Qt UI would change the size according to the logical DPI of the computer
Only Windows and Linux have been tested. (Should also work on Mac but have not tested).
The function is unfinished.

Fixes #576 
As an additional note if I set the print statements as follows:

<pre>
        print(args)
        print(args[0].width(), args[0].height())
</pre>

we see that the result is:
<pre>
(<freeseer.frontend.qtcommon.dpi_adapt_qtgui.QWidgetWithDpi object at 0x7f638d321df8>, 300, 300)
(640, 480)
</pre>