Issue #50
When in ScoreReport, press back button goes to main page. When you press back button again, it does not work properly (100 points)
Issue #43
Fix endless loop to make It real endless (50 points)
Issue #58
Fix layout of welcome page to make it suitable to different resolution (150 points)
Issue #59
Improve current Javadoc:
- Add description for each method's parameters.
- Elaborate current class and method description.
- Add comments for uncovered class and method. (150 points total)
Issue #60
Fix the bug in DEC to BIN quiz: switching to landscape and switching back causes answer textview to disappear. (150 points)