Added easing C code.

This is in preparation for the removal of the database blender
module.

In the future, this code may possibly be rewritten in Python.
Implemented initial JSON database loading
Implemented database blenddata module for JSON sources.

It retains most of the structure of the database blender
module.

Differences between blender and blenddata modules:

* Overall, much simpler interface.
* Removed of BlendFileData, BKE_Main, BlenderStruct, ListBase,
  ID.
* BlendData is analgous to BKE_Main and similarly
  ListBase -> Block.
* Primary changes are in the initialization functions.

The current database blender module is now deprecated and
will be removed in the near future.