simple online-training
simple online-training correct a bug
 add button hint
 add button online training. fix display bug when training from 1 type of characte to another type of character
 use gyroscope to tackle the problem that touching screen is recognizing as a stroke. solved problem
finished initial replacement in KNN. need more test
add KNN debug window
add error static and Shift&CapsLock
change training order
 added functions to provide more hints. use a new scheme of tie breaking for majority vote in KNN