.. there is a fixup for this in Qt 5.6 but not prior and
it causes horrible performance problems on the QXT
span slider on Linux, which is irritating when trying
to zoom into an area of a ride.
.. 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
Introduce a span-slider on the normal Ride Plot chart to enable
users to select a range to plot and scroll left and right. The
zoom to interval function now uses this slider rather than setting
a zoom range. Tooltips are now displayed on the normal and stacked
views to assist in reviewing specific data points.
Old style zooming still works as expected, but scrolling at a zoom
level is not yet implemented.
The qxt widget 'QxtSpanSlider' has been placed in the top
level directory (GoldenCheetah/qxt) alongside the qwt widgets to
avoid adding another dependency.
A number of optimizations have also been introduced to speed up
plotting in general. A new color setting for the thumbnail plot
has also been introduced. Refresh of the plot when data is changed
in the editor has been fixed. The zoom scale up/down widgets are
also disabled when in normal mode to avoid the bug highlighted by
Robert Carlsen.
Fixes#122.
