Tooltips, autoupdate and path

Improvements

• Tooltips
• First autoupdate check waits until the day after a fresh install
• Adds gpx.exe and gpxui.exe to the path

Bug fixes

• Endstop editing in the machine editor now work (rather than all changing
  the x endstop)
• Releases now include release notes built into the nupkg which prevents
  squirrel from barfing in the log