Bugfixes

I've enabled Unity's Crash and Exception reporting in the project's dashboard and I've now found some issues people have, that tool is really golden!

Main issues were caused by tournaments with all levels deleted (??) and/or negative time values (??). Not sure why people would enter negative values, but it's not possible anymore in any case.

Full changelist:

• fixed level indicator not increasing when using the buttons (how did I miss that?)
• not possible anymore to create levels or tournaments with negative values
• newly added levels copy the values of the current selected level
• duration of a level cannot be 0 anymore
• fixed a bug in the time displays where a time value could be NaN (fixed both cause and effect)
• fixed that at the very end of a tournament the next level sound would keep playing