Fix horizontal scrollers

.. from ever appearing on ride navigator / activity log
Fix crash when opening Speed histogram for the first time, on a file without speed info.

I had a trainer file as the second file in my history. Opening this ride, and selecting the speed histogram made GC crash.

I narrowed it down to line 905 in src/PowerHist.cpp. The code was trying to do a resize on a QVector with a negative value. count was -7.

Making sure that count is always 0 or greater fixed the crash.

Note that opening another ride file, with speed information before this one, selecting the speed histogram and only after that selecting the ride without speed information, did not crash the application. I'm suspecting that there might be some resetting of values, perhaps in the "standards" arrays, that is not done when a data series is missing.
Merge pull request #856 from ibooij/fix_crash_when_dataseries_is_empty

Fix crash when opening Speed histogram for the first time, on a file without speed info.
Allow Multiple Helper Widgets

.. in GcOverlayWidget.
CPPlot warning to qDebug

.. qmessagebox is a bad idea since user has not idea
   why it is being raised.
Allow Interactive Widgets in GcOverlayWidget

.. for "future" interactive widgets.
Add *.pri to .gitgnore
Faster W'bal algorithm

Using Andy Froncioni's modification to the original
formula that removes the need for Tau and also lets
the exponentials drop out.

Massive speed improvement!
Dialog deleteLater() om HomeWindow

.. trying to id the Mac crash.
Sort out Zones.cpp code formatting

.. I know its a matter of taste, but some of the formatting in there
   would win the OCCC competition. I mean FFS, who puts else clauses
   after a ';' !?

.. the formatting probably reflected the different people who have
   updated the code over the years.

.. no functional changes whatsoever in this commit -- just cleaning
   the source code to make it more maintainable (and readable)
Veloclinic Multicomponent Model

.. implementation of the Veloclinic model, or at least
   the first of a few potential models.

.. It may not be correct at this point, but committing
   a checkpoint.
CvsRideFile: Add Moxy file type
Correct errors in last commits
Bin2RideFile: Small improvement in sensor name parsing
QPixmap::grabWidget() deprecated

.. so use QWidget::grab() instead from QT5 onwards
Merge branch 'master' of github.com:/GoldenCheetah/GoldenCheetah
merge upstream into master