Compare Pane Table better color support

.. headings color and remove frame
Support Metric Names with "special characters" for Column Chooser Drag&Drop

!!! please check if this right way to do it.
... column names containing special characters (here greek "average"
sign) did not work in Drag&Drop (even though they should be part of
Latin-1 (after changing in Mime to UTF-8) not only the greek characters,
but also "TM" works without special treatment)
!!! is this valid for all platforms ?!!!

(cherry picked from commit b4d1a7d3041beec686c7262cfa65bac8cf6e2179)
Merge pull request #906 from Joern-R/pull1

Support Metric Names with "special characters" for Column Chooser Drag&D...
Move wpk array next to watts array in cache

.. so we can read them both in with a single
   read -- this is to support an update where
   pd estimates support wpk and absolute watts.
Clear Interval Summary on Ride Selection

.. otherwise its left with summary from previous ride.
Add WPK estimates to PDEStimates

.. but not plotted in LTM or shown o the
   summary chart yet
Show w/kg J/kg estimates on Ride Summary

.. and fixes up the calculation too.
.. still need to fix up the LTM plot
Add Estimates /kg to LTMPlot
Data Filter - Internal Field Names + Multiple tr()

... allow/use only internal field names (delivered by Column Chooser) in
Data Filter expressions
... multipe tr()

(cherry picked from commit bc4164adab74dd82c0a0307d7d0fbb736f95ef0d)
Merge pull request #907 from Joern-R/pull1

Data Filter - Internal Field Names + Multiple tr()
Searchbox rounded corners

.. gone in flat mode.
Merge remote-tracking branch 'upstream/master'