Clean up Switch files

Update icons for switch hog

ensure switch sprite color is black

update switch sprite

Improve Switch outline, add vector files

Update ChangeLog.txt and CREDITS

replace jungle with ogg

use different flag for vcpkg debug

Remove accidental DEBUG flag in Pascal builds

update sdl library name

remove nopng from vcpkg build

remove direct libpng dependency on windows

Remove usage of macdeployqt in favor of CMake BundleUtilities. BundleUtilities properly finds all dependencies and adds them to the .app automatically. It also fixes rpath and install_name issues for any of the binaries or dependencies

Fix compiling on MacOS X by requiring c++11 standard. Building now requires MacOS X 10.8+ and CMake 3.9+

Add build/ directory .hgignore

Make hardware acceleration optional on MacOS X

make sure keys.csv is installed

add background to switch animation

add crocodile hat

replace jungle with opus

start gear data group implementation

fix check for static gears

Restrict girder placement in other land objects, too

disallow placing girders over airmines and moving hogs