* Move *cache* methods up into the AssetManager interface from DesktopAssetManager * Fix various incorrect javadoc * Add new method to load an asset from an InputStream * Restructure DesktopAssetManager.loadAsset() to make it less monolithic
* Move *cache* methods up into the AssetManager interface from DesktopAssetManager * Fix various incorrect javadoc * Add new method to load an asset from an InputStream * Restructure DesktopAssetManager.loadAsset() to make it less monolithic