Fix W' work metric

.. the calculation assumed 1s recording (or was just wrong)
   joules are now calculated properly, this is especially
   important for SRM recordings of 0.5s samples
Fixup polarised zones for compare mode

.. the new option to show in polarised zones instead of
   the user defined zones now extended so it works when
   comparing date range / intervals.
Add Data Labels to Histogram Zones

.. when plotting in zones its helpful to have
   data labels to show the percentage or
   absolute values each bar represents rather
   than having to hover over it.
Tone down the toolbar shading

.. on QT 5.2.1
QT5.2 Remove VLC Dependency

.. if you are building with QT5.2.1 or higher we are no
   longer going to use VLC for video playback.

.. the QT Multimedia module seems to finally have made
   the grade and works as advertised on Linux and Windows

.. FOR NOW we will continue to use QTKit on Mac but that
   may also change soon.

This is to enable overlays -- placing the video behind the
charts etc.
Polarised Adjust Z2 to 85-100% of CP

.. seems to be a consensus.
Merge branch 'master' of github.com:/GoldenCheetah/GoldenCheetah
Allow drag and drop ride for compare

.. drag and drop a ride into the compare pane to get
   the entire ride rather than an interval.
Compare Intervals now Compare Rides and Intervals

.. changed the title of the compare pane to reflect the
   fact you can drop rides or intervals and compare both.
Zone Array is a count not time

.. Fix polarised zones being ZERO when recIntSecs is
   sub-second (e.g. 0.5s with an SRM).

.. the polarised zones were being updated to hold time
   rather than a count of samples. This was fine when
   recIntSecs is 1s but a problem  when it was 0.5
   .. because is is an integer!
Scale Y-Axis on Ride Plot

.. When you click on the axis to isolate it a spanslider
   appears to let you manually adjust the axis.

.. it looks naff .. but we can tidy that up separately
AllPlot Zooming Cosmetics

.. slider removed as it was ugly

.. handles are placed on the same side as the axis
   being manipulated, since its irritating to click
   on an axis then have to move mouse to the other
   side of the chart
Add Acceleration Data Series

.. to ride plot only at this point, but will add to
   CP curve etc later

.. will also need to add rate of change for HR, Cadence
   Power as well too.
Invisible handles on AllPlot

.. setPalette made no difference on Linux but did on Mac
   so reverting it out of AllPlot.h
Add Acceleration to the RideFileCache

.. so we can chart distribution and cp curve for it
Add Acceleration to CP curve

.. and fixup related bugs in ridefilecache
3 minutes of acceleration bests is enough

.. don't need anything beyond that!
Acceleration is m/s/s

.. so don't apply metric to imperial conversion and don't
   label it as km/s !
Fixup CP interval plot

.. w/kg and accel were a mess and the code didn't honour
   decimal places properly.
Added Support for Elite Supercrono PowerMag