Refactoring: level loading and scene building separated.
- logic objects (Spacecraft, DustCloud etc) can be created and then later added to a specific scene
- setting LOD load limits in the settings.xml now work propertly, both for ships and weapons
Complete refactoring of resource and WebGL management.
- ResourceManager (renamed from ResourceCenter) now loads all resources asynchronously
- ManagedGLContext class handles context specific WebGL management (serves as an enhanced WebGLRenderingContex)
- removed many unnecessary memory allocations and gl calls (vertex buffer handling)
- loading box uses shows progress status more precisely during asynchronous loading
- only the necessary things (bindings to the new WebGLRenderingContext) get reinitalized if the level is started over
- GameScreenWithCanvases class functionality improved
- canvas resizing works appropriately again
- the functionality to load the battle moved into BattleScreen