Added difficulty menu-background not working
It shows 3 difficulties, but the buttons do not work yet
Fixed graphics bugs
Added Fraction spreadsheets

Easy, Medium and Hard difficulties
database changes
Game retrieves and displays values from database
Excel code was removed and sql code was added
Added 3 Decimals Worksheets
minor database change
New Javadoc

Accidentally created a new javadoc
Fixed decimal evaluation bug
Merge remote-tracking branch 'origin/NewMenu' into develop
fixed merge errors mainmenu.java