digraphs: unicode 5.0 character details

digraphs: unicode 5.0 character details

Recreate the digraphs include with version 5.0.0 of the Unicode
Character Database, encompassing most of the glyphs missing from 4.1
(as well as minor category improvements).

Fix the generator to account for undefined 'script' values, which now
occur for private use characters which were previously (erroneously)
categorized as 'Common'.