Update PyQt4 to PyQt5

**Describe the solution you'd like**
All usage of PyQt4 should be updated to PyQt5

**Additional context**
PyQt4 is extremely old at this point, and unless there is a specific need, it should not be used

Note: This fix will include code cleanup/updates as necessary, as well as fix #71 and #79 

**Requester Info**
Leor Bleier, NASA GSFC\Code 582
