Save and restore current time and range when switching traces

Save and restore current time and range when switching traces

- ITmfTrace augmented with methods to return current time and current
range.
- TmfTrace implements the new interface.
- TmfTrace provides a method to return the default initial range offset
that can be overridden.
- TmfTrace initializes the time range when the first event is parsed.
- TmfTrace updates the current time and range on time and range synch
signals. The current time and range are only updated if they intersect
with the trace range.
- ControlFlowView uses the trace's current time and range when a trace
is selected.
- ResourcesView uses the trace's current time and range when a trace is
selected.
- HistogramView uses the trace's current time and range when a trace is
selected.
- TmfStatisticsViewer uses the trace's current range when a trace is
selected.
- TmfUml2SDSyncLoader uses the trace's current range when moving to a
new page.
- TimeChartView uses the trace's current time when a trace is selected.
- Reading of the first event to initialize the start time if moved from
TmfTrace.traceOpened() to TmfEventsEditor.createPartControl(), to ensure
that this always occurs before any signal handler is called regardless
of the order in which TmfTraceOpenedSignal is broadcast.

Change-Id: I82b5222521842fcbda28892f6e07c68a05dd8e2f
Reviewed-on: https://git.eclipse.org/r/8802
Tested-by: Hudson CI
Reviewed-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
IP-Clean: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Tested-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Reviewed-by: Bernd Hufmann <bhufmann@gmail.com>
IP-Clean: Bernd Hufmann <bhufmann@gmail.com>
Tested-by: Bernd Hufmann <bhufmann@gmail.com>
Reviewed-by: Patrick Tasse <patrick.tasse@gmail.com>
Tested-by: Patrick Tasse <patrick.tasse@gmail.com>