[HarfBuzz] Lemongrass HarfBuzz Hackfest, end of day 3

[Behdad Esfahbod]

Another day, another 20 commits got us this far yesterday:

- Fixed more Khmer stuff.  Multiple signs in the syllable are positioned
correctly now.  There remain 525, ie. 0.175% failures.

- Tamil, after a few quick fixes, was the first script to reach 0 failures!

- We then routed Tibetan to go through the default shaper (non-Indic), but
turned 4 additional global features for it (abvs, blws, abvm, blwm), and that
single change fixed all the failures.  All 90% of them.  So Tibetan is also at
0 failures now.  The change was a net deletion of code even.

- We then looked at Sinhala.  There were 15% failures initially.  After a few
fixes for Al-Lakuna-specific behavior, ie. forming reph only if a joiner is
present, and allowing rakars in weirdly encoded sequences (eg.
Consonant,Matra,ZWJ,Al-Lakuna,ZWJ,Ra), Sinhala is now at 622 failures, ie. 0.229%.

- In the process Devanagari failures went down from 560 to 552 (0.079%)

- The following scripts we have never looked at, but here's their stats given
current state of affairs:

  * Gurmukhi: 8.1% failures,

  * Malayalam: 3.3% failures,

  * Bengali: 2.5% failures,

  * Gujarati: 0.67% failures,

So hopefully those are the ones we will be looking at today.

That was it for yesterday.  More to come tonight.

Cheers,
behdad