Initial commit of model building

This gives us a chance to annotate the models in whatever way
we need.  I've added support for:

* Adding new top level keys.
* Updating anything in the 'operations' dict with new attributes
  (param annotations, operation annotations, etc).
* Merging in the data from _services.json into the 'metadata' top
  level key.

Things I've left out for the time being:

* Annotating snake case conversions for ops/params.
* Adding python types to the model types.
Merge branch 'service-descriptions' into develop

* service-descriptions:
  Initial commit of model building
Update import to use tests.unittest
Regen models with new build process
Add dev docs for botocore

Starting it off with how to build the models.
Add docs for model annotations format
Merge branch 'devdocs' into develop

* devdocs:
  Add docs for model annotations format
  Add dev docs for botocore
Allow a py_name or cli_name attribute in the model to override the automatic generation of those attributes.
Adding FloatParameter. Fixing issue with map types using json encoding.
Adding model and related files for AWS OpsWorks service.  Fixing bug in translate.py, still expecting a list of operations rather than a dict.
Bumping version number.