[Unit Tests] RelationshipsMatrix should return unmodifiable Map types
[Unit Tests] TreeModelViewerDragDropHandler refactor and Unit Test overkill
[Unit Tests] MRUMenuManager refactor and Unit Tests
[Unit Tests] StringUtils: add compareVersionNumbers() method and tests
[Unit Tests] CheckForNewVersionAction refactor and Unit Tests
[Unit Tests] ModelCompatibility uses StringUtils.compareVersionNumbers()
[Unit Tests] Some corrections to tests and tested objects
[Unit Tests] Add DiagramModelUtils and Nested Relations tests

* Also upgrade ArchimateTestModel for more utils
[Unit Tests] Add DeleteCommandHandlerTests
Merge branch 'unit-tests'
Updated the docs for the selection tools in three places to make it
clearer how they work, and the relation between the alignment tools
and the primary selection.
Merge branch 'help-clarify-selection'
Merge branch 'hotfix-2.7.1'
Include a link to the wiki about contributing code to Archi, for easy
reference from GitHub.
Make structural chain documentation clearer.

Clarify the documentation for structural chains: at least two
relations to make up a chain.
Move a section forward to make the content present it self in a slightly more
"sequential reading" friendly way.
[Unit Tests] Check for null
[magwas] Ubuntu Shell scripts combined into one script

* Provided by magwas (mag@magwas.rulez.org)
[SVG Export] Add Preferences Initialiser

* Add Preference Initialiser the "Eclipse" way
* One Unit Test was failing the old way
[Code Refactor] Use single recursive methods

* Let's be smarter about this, ok?
Merge PR #49