[indic] Minor
[indic] Improve base re-finding

No test numbers change.
[indic] Recover OT_H undergone ligation and multiplication

Sometimes font designers form half/pref/etc consonant forms
unconditionally and then undo that conditionally.  Try to
recover the OT_H classification in those cases.

No test number changes expected.
Fix base-position when 'pref' is NOT formed

If pre-base reordering Ra is NOT formed (or formed and then
broken up), we should consider that Ra as base.  This is
observable when there's a left matra or dotreph that positions
before base.

Now, it might be that we shouldn't do this if the Ra happend
to form a below form.  We can't quite deduce that right now...

Micro test added.  Also at:

https://code.google.com/a/google.com/p/noto-alpha/issues/detail?id=186#c29