Rename translator implementations to 'generic-...'
braillecss: misc bugfixes and additions

- prevent multiple @page rules with the same name
- default value of widows/orphans = 2
- css:get-property-value should not check for css:applies-to
- ...
Generalize 'TablePath' to 'ResourcePath'
Liblouisutdml: misc changes:

- configPath is now a URL, and can be a 'ResourcePath'
- table is now optional
- liblouis-formatter: don't register liblouis tables, copy them together with the config files to temp-dir
xml-to-pef: misc changes

- xml-to-pef.load step for loading components from URL's
- Add metadata in xml-to-pef instead of delegating to louis:format
- stylesheet option: add external css to document if and only of option is given
liblouis-calabash: output a sequence of louis:result instead of a louis:output with multiple louis:section
liblouis-formatter: large refactoring

- Split document into sections based on css property 'page'
- Automatically extract TOC's: 'display: toc' is not needed anymore
- Document sections and TOC's are now a single document stream
- Miscellaneous smaller changes
Deprecate display: toc