Work on creating a new TextureAtlas loader that uses Json files

- Uses Json.Serializable for most of the heavy lifting implementations.
- Unlike the current implementation, a lot of the source data loaded
from the file is private for only the TextureAtlas should really be
making use of the data.
- Called TextureAtlas2 for now until it can be a full drop in solution
for most users
Add the legacy atlas parser

- Also move Region and Page into the TextureAtlasData class
Throw in the modified AtlasSprite class

Actually required quite a bit because it creates sprites that maintain
and recognize the properties of how the texture region was parsed from
that atlas

-Region now has shared properites of the original AtlasRegion
Add writing of an atlas to json format
TextureAtlas2 files are now loading properly

Also added json writing for serializing