Data/Dialog/dlgChecklist_L.xml: Swap position of Prev/Next buttons

Use same arrangement as in the other dialogs.
Data/Dialog/dlgTaskPoint_L.xml: Swap position of Prev/Next buttons

Use same arrangement as in the other dialogs.
Renderer/FinalGlideBarRenderer: Render with transparency on OPENGL targets
FeedFlyNetData: Fixed pressure_vario calculation

When the vario goes up the pressure obviously must go down...
Driver/FlyNet: Implemented WindowFilter for the vario value

This filter was suggested by the manufacturer and has proven to work well
for the device. The static pressure is now passed unfiltered as the filter
was only necessary to get the jitter out of the derived vario values.

This fixes ticket #2381