clicking create event button too fast can break

[isaacpearl]

if you click the create event + button multiple times quickly, the first event creation may not register. this is probably because as each call to addEvent() makes a copy of and overwrites the events table in lua, the second call makes the copy before the first call is finished adding the event. there needs to be some kind of queue system to fix this, or just manually make it so you can only click the create event + button every x milliseconds.