Added method to set the character that triggers token creation

I wanted the EditTextView to create tokens when the user inputs a space, so I removed the hardcoded comparison with ',' and added some convenience methods to set the character that triggers token creation. 
It is possible to set multiple characters.

The code can be shorter by using a List instead of an array of chars, but given that char is a primitive I think the current approach is less resource intensive.

I hope I did this pull request thing right, I'm quite new to GitHub