- upgrade the configuration to a current version
- provide a frontpage with cross-links to other documentation
- define a set of modules; relevant classes and files can be
added to these, to create a exploration path for new readers
- fix a lot of errors in documentation comments
- use a custom configuration for the documentation pages
- tweak the navigation, the sections and further arrangements
* add a 'unknown' error to the error system as fallback
* lockerror.c|h define all errors which can happen due locking
* lumiera_lockerror_set() translates posix errors to lumiera errors
* remove stale errors from sectionlock.h