Windows - Menu bar - Mac / Style problem

... in Windows - Mac / Metallic style did not work any more, only flat
style color was shown
Merge pull request #914 from Joern-R/pull2

Windows - Menu bar - Mac / Style problem
Enable Curve Isolation on Trends chart

.. isolation used on AllPlot when hover on axes is
   equally useful on the LTM trends chart.
Show/Hide Labels on Curve Isolate

.. as LTMplot uses them a lot to mark values that
   are topN or lowN
Isolate Curve Labels but not Vertical Markers

.. as they represent intervals and events and are therefore
   related to the x-axis (time/distance) rather than any
   y-axis we may be showing / hiding.
LTM Marker colors

.. dash lines and red, makes it a bit more like
   the styling on allplot

.. might be interesting to add 'hover' on seasons.
Fixup initial geometry and positioning

.. some regressions in there (setting only saved on move)

.. will check the positioning and geometry are sensible regardless
   of whether they come from appsettings or defaults.
Don't wait - cancel - the pd estimate thread

.. it might take ages and we don't care about the results !
Fix font selection

.. should update when saved not restarted.
Merge branch 'master' of https://github.com/GoldenCheetah/GoldenCheetah into pull3