[Bug 7150] Implement Arabic shaping

[Wine Bugs]

http://bugs.winehq.org/show_bug.cgi?id=7150

------- Additional Comments From [e-mail]  2007-11-01 15:51 -------
Here is a suggested algorithm for handling missing shaped glyphs in the font,
from Ahmed Kamal:
Any character can take up to 4 forms (Initial, medial, final, isolated)
1- If Initial is missing => Use Medial form
2- If Medial is missing => Use Isolated form
3- If Final is missing => Use Isolated form

The isolated form is the one defined in the main Unicode area for Arabic, and so
must not be missing in any font presuming to contain Arabic letters.