Various IText fixes

- Double click directly into editing mode sets cursor position rather than selects whole word
- Mouse click after line sets cursor to this line - at the end of the line
- Flashing cursor now behaves like MS word (opacity is 1 while mouse is down and animation resumes on mouseup)
- Moved cursor setting and reinitializing into MouseDown handler (MS Word behaviour)
- Restart cursor on selectLine and selectWord to improve perceived responsiveness (MS Word behaviour)
- Fix selectWord so that double clicking at the end of a word (in the left half of the space) selects the previous word
- Fix center/right aligned cursor placement on mouse click when text box is scaled
- Fix click cursor placement when clicking to the left of the first line on centered/right aligned text (bug occured when the first line had a smaller width than any subsequent line)