pango windows: Support Windows XP

HarfBuzz uses ScriptShapeOpenType in usp10.dll but usp10 on Windows XP
doesn't have it... So we disable it to support Windows XP. :<

[ruby-list:49412]

Reported by myokaym. Thanks!!!
Add 2.0.2 entry
Add missing Kentaro Fukuchi to thanks list in 2.0.1

Sorry and Thanks!