Fix infinite loop when whitespace character overlaps boundary
Make tiler retry operation a bit more robust
Re-factor line breaking into the tile class entirely

Line breaking needs to be able cross run boundaries easily, in the case of no-break styled runs or runs with nothing but whitespace in them. The previous algorithm of find a run and then only break withn would fail in those cases.
Fix live lock when cursor moves over certain characters

Seems InDesign needs charcters to map to at least 1 glyph even if it's been used in another mapping
Fix whitespace at eol bug
Fix break-in-run handling