Added underlying support for asset deltas.
Removed dependencies on config from module manager (fixing unit tests).
Fixed an issue with conflicts between the hardcoded "special" materials and material assets, but adding a prefix to the names of all the special materials.
Added prefab delta support. A prefab delta can be included in a module under deltas\(ModuleName)\prefabs\(prefabName).prefab. These may add/remove and alter the fields components, as well as change the prefabs parent.  Deltas are applied in module dependency order, so if two modules apply changes to the same prefab, they module that depends on the other's delta is applied last. If modules without dependencies change the same prefab then the order is arbitrary.
Deprecated the BeforeEntityCreated event.
Added support for overrides and deltas to the module build.
Fixed a issue with ArchiveSource's scan for deltas and overrides.
Merge pull request #1070 from immortius/develop

Fixed incorrect registration of new block families client-side.
Merge pull request #1060 from immortius/develop-delta-prefabs

Delta support for prefabs.
Continue without sound if OpenAL setup fails
Don't setup player instance in headless mode
Fix & streamline the gradlew startServer config.cfg generation - second JSON pass was overwriting the first pass
Remove duplicate OpenAL library loading and add logging
Replace switch with only one case with if statement
Fixed warnings in asset package
Merge pull request #1071 from msteiger/fix_221

Continue without sound if OpenAL setup fails
Fixed most of the warnings in audio package

* Mostly trivial changes
* Roughly 100 warnings in total
* Mostly raw type warnings
* Missing override
* Hide inherited field (playing)
* Some casts were necessary
* And several per-method template names
* Covariant return types were used where appropriate
Split NetworkMode.SERVER into LISTEN_SERVER and DEDICATED_SERVER

Most follow-up changes are rather straight-forward
Added NetworkMode to NetworkSystem to be able to decide which mode to
enter.
Use StaticSound for sounds and StreamingSound for music assets
Made BaseSoundSource fields private
Added Static/StreamingSound to serialization libs
Removed BaseSoundSource playing member
Tiny tweaks - log statement, move "crouch" to "CTRL", rename binding descriptions for crouch and jump slightly
Use boolean flag to indicate NetworkSystem host mode