Issue : Missing `mainloop()` in `BondVis.py` and `HydroBond.py`

[PrinceSajjadHussain]

The tkFileDialog.askopenfilename and tkSimpleDialog.askstring functions in BondVis.py and HydroBond.py respectively require a main event loop to be running. However, neither of these files create or run a Tk() instance, so the dialog boxes will not appear correctly. While a Tk() instance is created in BondLab.py, it is not guaranteed to exist, or be valid at the time these other functions are called.