Refactored er_tag factories
Several refactoring. See below for more details.

1. Moved config file path from spec/lib/er/ to spec/config/
   because id and password parameters need to be shared to
   the er_user factory.

2. The er_user factory was refactored according to above.
   Now it has 'Default User' which has email and password
   specified by crawler_config.yaml

3. Added spec/lib/er/crawler_spec_helper.rb
   Some preparation code was moved there.

4. Some integration test code was added. (WIP)
Added a conf file under lib/config and change a constructor of crawler.

The crawler didn't have a config file other than the one for test so
added the one. This file is for fixed variables, not changed basically.
Used db values rather than values in config file for default user
Modified tag data in sample data files
Implemented scrape_and_save method in Er::Crawler.

And made the test order of rspec not be random.