Validation usernames extended to include dashes.

- fixed another bug where user should instantiate with legacy smf fields
Validation checks for smf legacy fields in users.
Legacy key implementation for User model.
Reduced username limit to 2 chars.
Update test ordering, post delete/purge pattern

Implemented the delete/purge pattern for posts. Updated the index.js
file to correctly route the posts interface.

Updated the ordering of all tests file to be inline with each other.
Import for post links imported legacy user_id
Added a test, for testing metadata.

* Currently test post_count for boards/threads and thread_count for
boards