improve GUI
label invisibility yes
change font and fix invisible border, hi light prob
Merge branch 'Ben's_branch' into linh-dev

Conflicts:
	src/todologApp/UserInterface.java
add popup functions and change exit/show/hide functions
add DBStorageStub
Merge commit '0515cf6de636bd43b622326e8a00a2f732fb556f' into vani's_branch

Conflicts:
	src/todologApp/ReminderLogic.java