[HarfBuzz] harfbuzz-ng: Changes to 'desrt-changes'

[Ryan Lortie]

New branch 'desrt-changes' available with the following commits:
commit e577f0e5e2d09e9e75f4e2abb7ac6e40a5e229de
Author: Ryan Lortie <desrt at desrt.ca>
Date:   Fri Apr 15 20:13:13 2011 -0400

    unicode: rework virtual functions for subclassing
    
    Unicode data providers can now be subclassed, including support for
    chain-up.  The interface should now be nicely bindable, as well.

commit 69c87e50e8fe745066747d5ea592242400373c78
Author: Ryan Lortie <desrt at desrt.ca>
Date:   Fri Apr 15 18:34:45 2011 -0400

    buffer: rename _ensure to _pre_allocate()
    
    The new name is more self-documenting.

commit 5554874f4bdfb90c85649e263f15d2a9d6a02509
Author: Ryan Lortie <desrt at desrt.ca>
Date:   Fri Apr 15 18:32:36 2011 -0400

    _get_glyph_{infos,positions}: length out parameter
    
    Return the length of the arrays.