migrate data access to SQLAlchemy.
remove unused import.
changes reflecting the requirements to merge.
let sqlalchemy handle schema creation; also pgsql
Merge pull request #1 from chooper/alchemy-schema

let sqlalchemy handle schema creation; also pgsql
remove reference to nonexistent schema.sql in setup.
Handle cases, when code is not being run from virtualenv.
Merge pull request #12 from deathowl/master

migrate data access to SQLAlchemy. Add Mysql supported schema also.