Supplemental characters not output properly in encoders/writer

[Former user]

Original [issue 28](https://code.google.com/p/okapi/issues/detail?id=28) created by @ysavourel on 2009-03-19T04:37:05.000Z:

The supplemental characters are output as simple chars in the XML encoder, instead of the NCR value for the pair. The problem comes from char vs codepoint when detecting the need for escape of not. This problem is likely prevasive throughout the ocde.

[Former user]

Comment [2.](https://code.google.com/p/okapi/issues/detail?id=28#c2) originally posted by @ysavourel on 2009-03-24T03:06:20.000Z:

Fixed in GenericSkeletonWriter and all the encoders.