Text Selection hybrid approach

PDF-990 captured a major rework of the the text selection algorithm from a text box inclusion mechanism to mouse based start/end detection.

The text box solution work well but had a few corner case issue that didn't allow text on two lines to be easily selected but it work very well for multiple page selections. The new approach in PDF-990 worked a lot better for selecting text on a line by line bases but was susceptible to missing lines if a user moves very quickly from one page to the next.

This bug will capture the work needed to bring these two approaches together to get a solution that has no limitation.