Added callback methods for buttons in GUI.

Methods for BPM add and substract, add and substract for time.
Started making functions for getting and setting properties to file.

 Incheckare: Marcus <marcux@localhost.localdomain>

 På grenen master
 Din gren är à jour med "origin/master".

 Ändringar att checka in:
	new file:   db/__init__.py
	new file:   db/file.py
	modified:   ui/mainWindow.py