[430527] Change providerName to Eclipse Modeling Project

This is what we are supposed to do from my interpretation of
http://build.eclipse.org/simrel/luna/reporeports/reports/providerNames.html

Bug: 430527
Change-Id: I0df426fd27460cf8b14668fd1dd57c8e6041bf68
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>
[427803] Fix a regression in customization made during split.

Bug: 427803
Change-Id: I9a96392c612ea0c3a920fa250ad98d17cf6a1234
Signed-off-by: Laurent Redor <laurent.redor@obeo.fr>
[431634] Additional cleanup

Several dispose have been completed, a final static image has been
removed (its descriptor is still use as constant, the image is not
created on each call, as it is contained in the DiagramUIPlugin image
cache.

Bug: 431634
Change-Id: I9c279d5a590e17764e5cf8934d2ef2f720ca2546
Signed-off-by: Maxime PORHEL <maxime.porhel@obeo.fr>
[431634] Improve tabbar contributions

Merge SetStyleToWorkspaceImageContributionItem and
DeleteFromDiagramContributionItem in SiriusActionBarContributionItem
(used in old ui, to populate the main action bars). 
Use the TabbarActionContributionItem to add the correspondign actions in
the tabbar: it uses the part selection service and not the page's one.
Modify the TababrActionContributionItem to add the capability the action
enablement through selection change propagation.

Bug: 431634
Change-Id: I8677f209a6a40fb7cec42f9b3e129c288e41dc6e
Signed-off-by: Maxime PORHEL <maxime.porhel@obeo.fr>
[431634] Dispose tabbar context service as soons as it is possible

This helper is used during tabbar population only, it must be disposed
when population is done, there is no reason to wait for release
contributions.

Change-Id: I8b9df1aa7ede9770e8140eae92a59788bf983c01
Signed-off-by: Maxime PORHEL <maxime.porhel@obeo.fr>
[427803] Change label of action ExportRepresentationsFromFileAction

and also for ExportRepresentationsAction

Bug: 427803
Change-Id: I86a16f141ac85ed2eebace0c93b4c60df7cf6720
Signed-off-by: Laurent Redor <laurent.redor@obeo.fr>