- new method to get elementAt on execution specification, and access to
nested executions
- command to create a nested execution, that may be refactored with
some commons of the insertExecutionCommand on lifelines
- Add some tests
- handle destruction of nested executions (and their related messages /
nested lifelines in chain)

Some points left:
- adding a nested execution always nudge parent exec, where it should
not if there is enough space
- no side is currently handled for the nested execution representation
- getNestedExecution() may rely on recently introduced getCovered() for
#52


Change-Id: I50589eb0e4ae7b850579d6e1cad5966937dffa4c
Signed-off-by: Remi Schnekenburger <rschnekenburger@eclipsesource.com>

- Check and update model generation for test and model plugin from
seqd.ecore
- do not update edit plugin (formatting issues with current version on
the server)

Change-Id: I532032620ae40c29412ef113f183709a4cc25b5c
Signed-off-by: Remi Schnekenburger <rschnekenburger@eclipsesource.com>

- update the nudging policy to be similar to the current implementation
of standard executions
- 2 issues in the tests: 1 is ignored (but not by my dev env) as the
test is not implemented yet, and one that can be reproduced by hand: if
a lifeline has an execution with a nested execution, it can not be
deleted.

Change-Id: I4b52b6d0a7248dcfe01365c40d559602d30406c5
Signed-off-by: Remi Schnekenburger <rschnekenburger@eclipsesource.com>

- update lifeline API with a method to get first level executions to be
able to remove only these executions. Nested ones will be remove in
chain by the remove execution command
- update tests

Change-Id: Iae629bd73730a75880ecdb4ff263aaefd7428ac7
Signed-off-by: Remi Schnekenburger <rschnekenburger@eclipsesource.com>

- Develop additional tests for complex scenarios (dependencies with
messages between different lifelines)
- 2 tests are failing, but this seems independant from the nested exec
spec, as it fails even if they are removed from initial model.

Change-Id: I56794a50383e3e4d793ffa62d49089188f2c8f2a
Signed-off-by: Remi Schnekenburger <rschnekenburger@eclipsesource.com>

Conflicts:
	plugins/org.eclipse.papyrus.uml.interaction.model/model/seqd.ecore
	plugins/org.eclipse.papyrus.uml.interaction.model/model/seqd.genmodel
	plugins/org.eclipse.papyrus.uml.interaction.model/src-gen/org/eclipse/papyrus/uml/interaction/internal/model/SequenceDiagramPackage.java
	plugins/org.eclipse.papyrus.uml.interaction.model/src-gen/org/eclipse/papyrus/uml/interaction/internal/model/impl/MExecutionImpl.java
	plugins/org.eclipse.papyrus.uml.interaction.model/src-gen/org/eclipse/papyrus/uml/interaction/internal/model/impl/MLifelineImpl.java
	plugins/org.eclipse.papyrus.uml.interaction.model/src-gen/org/eclipse/papyrus/uml/interaction/internal/model/impl/SequenceDiagramPackageImpl.java
	plugins/org.eclipse.papyrus.uml.interaction.model/src-gen/org/eclipse/papyrus/uml/interaction/model/MExecution.java
	plugins/org.eclipse.papyrus.uml.interaction.model/src-gen/org/eclipse/papyrus/uml/interaction/model/MLifeline.java
	tests/org.eclipse.papyrus.uml.interaction.model.tests/src-gen/org/eclipse/papyrus/uml/interaction/model/tests/MExecutionTest.java
	tests/org.eclipse.papyrus.uml.interaction.model.tests/src-gen/org/eclipse/papyrus/uml/interaction/model/tests/MLifelineTest.java

- generate code from ecore model after merge
- Add functional test for creation

Change-Id: I08bd36736552dbe715c426107c7108a50cd20b20
Signed-off-by: Remi Schnekenburger <rschnekenburger@eclipsesource.com>

- avoid issue on nested executions when reparenting the parent execution
on another lifeline using start message + add functional test
- fix typo on Occur'r'ence variables
- use Optionals#as in ExecutionSpecificationCreationEditPolicy
- improve code readability in MLifelineImpl
- update test in ExecutionSpecificationCreationEditPolicyUITest to avoid
issues on Mac.
- Fix header in InsertNestedExecutionCommand
- restore deleted test after merge

Change-Id: Ic08bb70eee73fb235fcb46876628e939deafdf14
Signed-off-by: Remi Schnekenburger <rschnekenburger@eclipsesource.com>

- Remove attempt to fix computation of coordinates in the
LifelineBodyFigure (currently, same code as overridden method)

Change-Id: I903b3c23925f5f74298119861beaa4ba6e729a2e
Signed-off-by: Remi Schnekenburger <rschnekenburger@eclipsesource.com>

- Fix test failure on MAC (no assume on y position at the beginning, but
compute the initial position and then check element position compared to
this initial position)

Change-Id: I84df77c862bffa4faa7826b9d341af0ba3b55c81
Signed-off-by: Remi Schnekenburger <rschnekenburger@eclipsesource.com>