Support (Swiss) German braille code

[bertfrees]

To do:

• Integrate German liblouis tables
• Integrate German libhyphen tables
• Currently SBS's braille translation system involves an XSLT that uses multiple liblouis tables. That functionality probably needs to be ported to the new system somehow. (see Integrate translation part of dtbook2sbsform.xsl sbsdev/pipeline-mod-sbs#2)

Depends on:

• Liblouis table for (Swiss) German liblouis#5
• Higher level translator components for all languages issues#14
• Integrate translation part of dtbook2sbsform.xsl sbsdev/pipeline-mod-sbs#2

[bertfrees]

@egli I suggest that we somehow extract the translation stuff from dtbook2sbsform and make that into a DTBook specific CSSBlockTransform (see CSSBlockTransform.java). Next we convert that into an EPUB3 specific CSSBlockTransform.

With this approach you'll end up with something close to your current solution. Not sure if that's desirable or not though.

An alternative is to convert the DTBook/EPUB3 specific semantics into more generic data attached to the text nodes (e.g. with CSS) and to pipe that into a common translation step.

Independent of the question above about more/less generic code, there is the question of XSLT vs. Java. Your current solution is almost entirely XSLT. The new systems allows for more things to happen in Java.

Something to consider in all this is that it's probably desirable to have similar code for all languages.

[bertfrees]

The liblouis tables live in sbsdev/sbs-braille-tables (branch pipeline2). The libhyphen tables live in sbsdev/sbs-hyphenation-tables. Both are dependencies of snaekobbi/pipeline-mod-sbs.

A stub for a custom CSSBlockTransform has been created: see sbsdev/pipeline-mod-sbs@511bf78. sbsdev/dtbook2sbsform should be ported to this stub.