util.isSplitable() accepts now also the previous char to help
decide if a space can be used to split a line.
TextBoxWidget:_splitCharWidthList() : simplified logic
util: made isSplitable() accept an optional next_char
for wiser decision
textboxwidget: speed up rendering, enhanced text wrapping,
allow selection of multiple words with Hold.
scrolltextwidget: allow scrolling with Tap.
Details in #2393