Add TideMapLoader

Modified other classes as necessary to support the Tide loader.
Merge branch 'mapsapi' of https://github.com/libgdx/libgdx into mapsapi

Conflicts:
	gdx/src/com/badlogic/gdx/maps/tiled/TiledMapRenderer.java
	tests/gdx-tests/src/com/badlogic/gdx/tests/TiledMapAssetManagerTest.java
	tests/gdx-tests/src/com/badlogic/gdx/tests/TiledMapDirectLoaderTest.java
	tests/gdx-tests/src/com/badlogic/gdx/tests/bench/TiledMapBench.java
Add TideMapLoader

In addition to adding the loader for tide maps, added tests for the loader
and modified some classes to accomodate the Tide loader.