Add a toString() for RebaseInteractivePlan.PlanElement

Helpful for debugging.

Change-Id: I4a31630edc37943bf1bd413df595feb4d275c69d
Signed-off-by: Konrad Kügler <swamblumat-eclipsebugs@yahoo.de>
[Rebase Interactive] Move multiple commits

This change is implementing moving multiple commits with the move
buttons. Drag and Drop will be done in another change.

Bug: 431450
Change-Id: Ifcb97a495a3a938f86d3a7370f61b777cd7b3672
Signed-off-by: Stefan Lay <stefan.lay@sap.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Initially disable buttons in branch selection dialog

The enablement of the buttons in the branch selection dialog depends on
the highlighted initial branch. But if there is no initially highlighted
branch, then the delete and rename buttons should be disabled (as it
already happens for the okay button).

The buttons will automatically be enabled if there is some initial
branch highlighting, as that is evaluated afterwards (see existing
comment in line 327).

Change-Id: Ic22fbfbc7694f6f672f3426614fe0a0b2e68fb67
Signed-off-by: Michael Keppler <michael.keppler@gmx.de>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>