Changes

Fix an issue with the compatibility with Java 7

Change-Id: Ib871d05080e30330f5082c0e2a38919b371ba92e
Signed-off-by: Stéphane Bégaudeau <stephane.begaudeau@obeo.fr>

Fix reference widget actions to be executed in the editing domain
adapter.

Change-Id: I313ded48ac668ceb950a73647e4d5be33ef8cff6
Signed-off-by: Mélanie Bats <melanie.bats@obeo.fr>

Fix radio group modification.

Add selection listener on buttons instead of the group.

Change-Id: I86a6ff6052fda010c450c6ce8a96ec9465dfc952
Signed-off-by: Mélanie Bats <melanie.bats@obeo.fr>

Add missing Javadoc to avoid CheckStyle error

Change-Id: I1da92296935b90103412ffb013c0e4909674cefa
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>

Add support for null values in combos

JFace ComboViewers do not like null values in their possible choices,
but null is a legitimate choice for optional references (meaning
"unset"). Replace nulls with a special value (with no risk of conflict
with anything elese) when filling the combo, and convert it back to null
when passing it to the controller if the users chooses it.

Also avoid triggering the controller's updateValue() callback during
refresh when we configure the combo to show the current value.

Change-Id: Ic3d4f53f8c7f5c11a6aee02ef59708024bd63154
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>