Automatic merge of T1.5.1-963-g375f79869 and 16 pull requests

- Pull request #799 at dfc715e: Consolidated wind simulation
- Pull request #839 at d00beb9: First phase of https://blueprints.launchpad.net/or/+spec/additional-cruise-control-parameters
- Pull request #876 at f92de76: docs: add source for documents previously on website to source Documentation folder
- Pull request #882 at 2a356fd: Blueprint/train car operations UI window
- Pull request #891 at 9a1d6b2: Auto save
- Pull request #892 at 1f5ba4c: Signal Function OPP_SIG_ID_TRAINPATH
- Pull request #896 at 5866028: First implementation of https://blueprints.launchpad.net/or/+spec/specific-sounds-for-ai-trains
- Pull request #900 at c27f32d: DMI updates
- Pull request #903 at 4742fa3: Downloading route content (Github, zip)
- Pull request #912 at 982afb6: New Triple Valve Features Vol. 2
- Pull request #919 at 26cc6a8: Added mouse wheel support for controls which can be moved by pressing t…
- Pull request #922 at abe2e52: Autopilot for timetable mode
- Pull request #923 at 4c27204: Add curve squeal to route
- Pull request #939 at 15ba46b: Add KM/HOUR/MIN to Cabview Units + Custom Units
- Pull request #940 at f8b5b15: Browser HUD column alignment improvements
- Pull request #943 at 7eebedc: Cab View Dynamic Brakes Indication Fix

Author: openrails-bot