SQLAlchemy data layer initial support

Initial support for SQLAlchemy data layer.
eve.io.sqlalchemy: decorator for SQLAlchemy model schema discovery
eve.io.sqlalchemy - initial commit preprared for pull request

SQLAlchemy support synchronized with HEAD
eve.io.sqlalchemy - fixed PEP8+PyFlakes warnings
Merge branch 'develop', remote-tracking branch 'upstream/develop' into develop
SQLAlchemy data layer initial support

Initial support for SQLAlchemy data layer.
eve.io.sqlalchemy: decorator for SQLAlchemy model schema discovery
eve.io.sqlalchemy - initial commit preprared for pull request

SQLAlchemy support synchronized with HEAD
eve.io.sqlalchemy - fixed PEP8+PyFlakes warnings
Merge branch 'sqlalchemy' of github.com:Tefnet/eve into sqlalchemy
eve.io.sqlalchemy - fixed flake8 warnings
Merge branch 'sqlalchemy' of https://github.com/Tefnet/eve into sqlalchemy
merge