Automatic merge of T1.6-108-g8fb3285d6 and 13 pull requests

- Pull request #1156 at f46d5f2: Fix incorrectly disabled options in train operations window
- Pull request #1091 at 492795a: Automatic speed control
- Pull request #1120 at ba3c47f: Automatically Calculate Friction Values if Missing
- Pull request #1121 at 91d2d26: Manually Override Articulation
- Pull request #1124 at e241a0d: Built-in PBL2 brake controller
- Pull request #1157 at 39cd994: Dynamic brake authorization by TCS
- Pull request #1159 at 48c9a63: Skip OR warnings about TSRE-specific token Ruler
- Pull request #1162 at 2516cce: specifies precedence of DDS over ACE
- Pull request #1163 at 2f9e292: Fix: Crash when using Camera 8 and F9.
- Pull request #1164 at 1ad9889: Fix: F9 crashes with a front coupled single steam locomotive by Csantucci.
- Pull request #1082 at 0cf717c: Allow variable water level in glass gauge
- Pull request #1128 at 086d502: Particle Emitter Overhaul
- Pull request #1160 at 9dc6b3b: Route Based TTrack Sounds

Author: openrails-bot