clean up after MonoDevelop/Visual Studio
fixed Dune 2000 powerdown cursor palette
don't play crumble sound when placing concrete
add the beacon button artwork to RA, D2k and TS

thanks to @xanax
Fixed #3826
Upgrade to SDL 2.0.3 and latest SDL2-CS (e8731ef).
Fix a visual glitch in OSX.
Add changelog entry.
Merge pull request #5073 from pchote/sdl-spaces-yaaaaaaay

Upgrade to SDL 2.0.3
Update structures.yaml

Removed CanPowerDown trait
Merge pull request #5093 from Mailaender/beacon-buttons

Added the Beacon button artwork for Red Alert, Dune 2000 and Tiberian Sun
Merge pull request #5089 from Mailaender/clean-msbuild

Enhanced Makefile to clean up after IDE mess
Fix volume slider order in the settings panel. Fixes #5088.
Merge pull request #5102 from pchote/volume-slider-fix

Fix volume slider order in the settings panel.
Fixed dialog.png for RedAlert
Merge FileFormats dll into Game and reorganise namespaces.
Added some notifications, fixed Cyborg/Cyborg Commando death sounds.
Added build/deploy, damage and destruction sounds to buildings and MCV.
Moved ^Wall default right below ^Building inside defaults.yaml.
Changed Cyborg armor type to Light, to make it less OP against other infantry.
Added Radars, Tech Centers and Walls to both sides.
Added idle animations to weapon factories.
Added some general prerequisites (FACTORY, RADAR, TECH).