Automatic merge of T1.5-rc3-78-gcf1e833bc and 13 pull requests

- Pull request #630 at 704731a: Sky Color Fix (Addresses Trello Roadmap Card #367 for More accurate sunrise and sunset)
- Pull request #652 at 918fdb1: Add button functions to Raildriver
- Pull request #677 at c1c417f: Correct double heading bug
- Pull request #706 at 265d33d: Extended door functionality
- Pull request #713 at 49c4ce8: https://blueprints.launchpad.net/or/+spec/cruise-control 
- Pull request #719 at fd9e47a: Upgraded to MonoGame 3.8.0 (+ small update for other libraries)
- Pull request #722 at fb9079e: Fix Windows Forms deprecations in ActivityEditor
- Pull request #732 at efbc397: Improvements for air brakes
- Pull request #733 at 72947b0: Fixed battery switch sound being repeted
- Pull request #734 at 8f8484c: Fixed battery switch timer not working properly
- Pull request #736 at a845085: Replaced truncated brake token table with lists
- Pull request #740 at b3e66ca: Refactored the circuit breaker and the traction cut-off relay in order to use the same design pattern as the C# signal scripts (compatible with current scripts)
- Pull request #741 at 2dd56ad: Fixed brake controller script not being loaded in timetable mode