This allows the Indic shaper to request decomposed characters.  This will
handle split matra for free.  Other shapers prefer precomposed
characters.

Instead of always applying those two features before the complex shaper,
let the complex shaper decide whether they should be applied first.

Also add stub for Indic's final_reordering().

Still not much there.

Copied form HarfBuzz.old Indic data.  These are below and post
consonants.  This is temporary.  Read the comment in the patch.

Using an incredible tool called Ragel.

Matches OT types now.

Nothing functional in there yet.

So far, we're parsing IndicSyllabicCategory.txt and IndicMatraCategory.txt
fils from Unicode Character Database and store them in an array to be used
by the shaper.  Also hooked up the shaper, but it does not do anything
right now.