Changed `plantuml-indent-regexp-group-start' to cover all cases
mentioned on sequence diagram page of the plantuml website. Added
tests for all elements-with and without label (text following the
keyword).
* fixed indentation code and added de-/activate to indentation
* added tests for indentation changes
* changed indentation code and tests
- more changes to plantuml-indent-regexs
- added more test
- changed function to determine indentation level and tests accordingly
- changed plantuml-indent-line and tests accordingly
- changed test names and doc strings to be more consistent
* more indentation tests, corrected regex for par block
- the par block usually does not have any label
- added database to start regex and added a test
- added block tests