Tess_CheckOverflow when writing long text

[illwieckz]

I first thought I reproduced #2014 but it was another bug according to @slipher and @DolceTriade.

The log isn't the same of course.

Warn: Tess_CheckOverflow: verts > std::max (10004 > 10000) 

The crash that happened is likely unrelated (and is known to not happen on nexe).

@slipher said to have reproduced it by typing 20 lines of text.

[necessarily-equal]

This may also be solved by caping text length