- new cvar fs_assetsPathJKA; works similar to fs_assetsPath, but automatically tries to detect jka rather than jk2 (using registry keys on Windows and known paths on Mac)
	- new cvar fs_noJKA; disables loading of jka assets
	- jka assets are loaded before jk2 assets, thus jk2 files take precedence in case of conflicts
	- .shader files from jka assets are virtually renamed to .shader_jka and .shader_jka files are loaded with lower priority than .shader files
	- when trying to load an image the renderer tries to load all extensions without considering the jka assets and only includes jka assets if all extensions failed; this avoids cases of a higher priority extension images from the jka assets overriding jk2 images

…AssetsDirectoryJKA.

…stent with existing cvars.

…g the cvar from fs_noJKA to fs_loadJKA).

If fs_basejka is not explicitly set as launch argument:
	- if fs_assetspathjka is set on launch (either manually or via detection for non-portable versions) the fs_basejka cvar is set to "base"
	- if fs_assetspathjka is not set on launch the fs_basejka cvar is set to "basejka" to make it easier to manually provide assets