tmf: Support drag move in time range histogram

tmf: Support drag move in time range histogram

- Add support for bucket display offset in histogram
- Middle button or Ctrl-left button are used to drag the window in time
range histogram
- New time range is propagated when the mouse button is released
- Remove restriction of selection buckets to visible range in data model
- Adjust histogram tool tip according to bucket display offset
- Prevent histogram tool tip when mouse is not over visible time range

Change-Id: I9ee3663511b57ac32a668cc25cf97e903a72e60f
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-on: https://git.eclipse.org/r/18309
Tested-by: Hudson CI
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
IP-Clean: Bernd Hufmann <bernd.hufmann@ericsson.com>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
IP-Clean: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>