tmf: Fold ITimeEvent2 into ITimeEvent

tmf: Fold ITimeEvent2 into ITimeEvent

Also split the one method in ITimeEvent2 into two separate ones,
since the Pair object was never used, so we can return the two
separate values directly.

Change-Id: Ia711b9cacf803b3afab1982a831478aef0bc38e1
Signed-off-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Reviewed-on: https://git.eclipse.org/r/38039
Reviewed-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-by: Hudson CI