Less subtley on interval hover

.. just a bit easier to see with less alpha.
Fixup button bar with lots of texts
Oops needed to set Min Width not Fixed

.. otherwise if smaller than window leaves a nasty
   blank render to the right of the buttonbar.
Move release files to GitHub releases

Uploaded binaries to GitHub and linked to release information.
Updated web pages to point to new binary locations.
Fix LTM legend colours

.. when user changes the background color for charts the
   legend can be difficult to read as it is always in black.

.. we now update the legend and it's widgets to change the text
   color when the chart is refreshed.
Fix stylesheet for 'More...' when config changes
Fix SEGV on add chart with Qt5

.. and also selects the first chart on the chartbar at startup.
HrPw honours background color preferences

.. bringing it in line with the other charts honouring the
   background color chart preference.
TreeMap plot honour background colors
PMC Chart honour background
Bing Map honour background

.. and small cosmetic fix for google map to be right colors
   whilst loading the map too .. stop nasty flicker.
3d plot honour background color

.. it already had plot background just needed to honour for
   the frame too.

.. also fixed default empty window to use correct colors.
Always signal when color changed

.. even if changed to same value to ensure the widgets
   are updated to reflect -- especially if setting to the
   same as the default value.
Aerolab honour background colors
Colors.h missing in ModelPlot.cpp
Fix Palette for Details

.. not quite right on Linux/Win.
Add Power 'heat' to RideFileCache

.. to indicate which power-durations are getting worked hardest

.. Calculate a 'heat' score for the power duration curve.
   A score that counts how many rides in the aggregate
   have a power-duration best that is within 10% of the
   best value calculated.

.. next step is to add it to the CP curve (when showing
   power) to provide some kind of shade/heat indicator
   for the area of the curve.
Fix ButtonBar paint error

.. caused by an eventFilter not returning false and therefore
   always filtering out the events on the chartbar and buttons.
Add Heat to CP chart.

.. from an idea from Michael Puchowiz during discussions
   about a Multicomponent PMC.
CP heat is only below the curve

.. makes it much easier to read and interpret!