dlgStartupAssistant.cpp: don't show Configuration if accessed via menu

During normal startup, this dialog shows the quick configuration
dialog first.  If accessed directy from the "help" menu,
dlgStartupAssistant should not show the configuration screen.
TaskManagerDialogUs.cpp: declare task automatically on exit

fix but where it was not declaring to the logger when present
ButtonRenderer.cpp, SDL/Canvas.cpp: make buttons round

More distinct.  GDI/Canvas.cpp not changed, so GDI will have
a mixed styles of buttons.
WaypointListSimple.cpp: if too many waypoints, show only closed bunch

Sort large list by distance and truncate list to include those
closest.
Infoboxes/Panel/Base.cpp: build margin around Close button

The problem is that users see the Close button at the bottom of the
screen and it looks like a Bar with no margin, and it is not clear
that they need to click it.  Margin makes it more visible as a button.
InfoBoxes/Panel/Home.cpp: new panel popup

Allows pilot to set the Home waypoint
InfoBoxes/Panel/GrAverage.cpp: new IB popup window

Lets the user set the average time for the Gr average calculation.

This is also available under the Advanced configuration settings.
windSettingsPanel.cpp: hide properties based on auto_wind value

don't show manual settings unless manual is selected etc.
SiteConfigPanel.cpp: add file download URLs to help text
dlgConfiguration: portrait, move close to lower left.

We're always putting close in lower left now.
dlgAirspaceDetails.xml: move "Close" to bottom left of screen
InfoBoxes/Content/Task.cpp: add Home Altitude Required infobox.