InfiniTime

Tile event handler : read the event data only if the event is a "value changed event". LVGL sends many other event and some of them do not set the event data (global static variable) to a valid address, which may cause an invalid read. I noticed that when porting this class on RISC-V platform (BL602).

Fix compile warnings

Fix slow scroll

Correct spelling issue in documentation (#509)

Fix cases where Get() isn't used