api.js

- library/lib/nxdoc-core.tcl: Major refactoring accomplished: Managed to refactor the validation code into a separate module, obtain a better separation between the backend implementations, ... Relocate the validate() method implementations into the Validator mixin layer. Validation (the validate cascade) is now triggered from within the mixin layer ... further improves the separation of concerns in nxdoc ... Also, moved frontend code into two distinct Tcl packages: We now distinguish between the DC ("Documentation Comments") and the XODoc frontends. I also remastered the entire frontend handling and disentangled the various concerns: specifying documentation sources, 1st- and 2nd pass handling, etc. - Support for document multiple Tcl packages per NXDoc project. Multi-package support, plus validation mode for packages, adding missing files to the repo - tests/doc.test: General cleanup, deactivated some tests for the time being (till the DC interface settles) - library/lib/nxdoc-core.tcl: Removed dead comments and dead codex - YUIDoc template suite: Added Monikas recent adaptations/extensions. I still have to check the resource paths for the xowiki backend, which are most probably broken for now. - Adjusted TODO for accomplished tasks.