Extracted new method for registering resource on the fly.

Refactored Eve's configuration handling and created Eve.register_resource()
method. If there exists given resource in the config, its settings is
overwritten by calling this method.

This may be base method for all ODM/ORM adapters which create schema out of
model and need to add it into Eve's config. #126
Added tests for Eve.register_resource().

#126.
Fixes in identitation to make Travis happy.
Merge branch '126-register-resource' of https://github.com/hellerstanislav/eve into hellerstanislav-126-register-resource
Sphinx attributes for #160.
New method Eve.register_resource().
Stanislav Heller
Merge branch 'hellerstanislav-126-register-resource' into develop