[HarfBuzz] vertical text for RTL scripts?

[Phil M Perry]

Just a clarification on the HarfBuzz.pdf document that I referenced, to 
answer any questions in advance.

1. Each example is given with a title (e.g., TTBHebrew) and horizontally 
LTR the RAW input text characters, as fed to HarfBuzz::Shaper.

2. The HarfBuzz-shaped output starts on the next line down. LTR starts 
near the left, RTL starts at the right margin on page 1.

3. The vertical examples (page 2) have a horizontal line with a dot in 
the middle, showing the alignment (starting point) of the write(s). For 
the "Hi There!" text (first two), 3 alignments are demonstrated: 
Beginning (default), Center, or End of the text falls on the starting point.

4. The HarfBuzz-shaped text has a little arrow showing where the next 
write would be for my library, and the direction of growth.

Phil