Put OmniAuth into test mode under development environment
Minor refactor to use "unless" in sessions_helper.rb as a modifier
Changed default database to tinder/tinder1
Refactor Piece#versions tests
Refactor Piece#versions examples
Refactor Piece#drafts examples
Refactor Piece#current_version examples
Refactor Piece#title examples
Refactor Piece#content examples
Refactor Piece#blurb examples
Refactor Piece#short_title examples
Refactor Piece#user and Piece validation examples
Add Piece#title= and specs.

Refactor Piece#title to work with #title=.
Refactor Piece#short_title to return right title after it is changed.
Add Previewable module and specs to handle shortening the title.
Add Piece#content= and specs.

Refactor Piece#content to work with #content=.
Refactor Piece#blurb to return right content when it is changed.
Add BLURB_LENGTH constant to Previewable module.
Use Previewable in Version#short_title, #blurb
Add examples for Piece#user and user valdation
Add Piece#changed?; initial immutable versions

Add Piece#changed? to see if the piece has been modified in a meaningful
way since fetched from the db.
Add a before_update callback and add tests to support immutable
versions. A new version is created by the Piece when it is modified
and saved.
Add immutable versions to PiecesController#update

Move business logic of creating a new version for a Piece when updating
it to the model.
This is known to fail 2 tests in the suite, so that an invalid
version isn't caught when updating the piece.  This will be fixed
shortly.
Updated readme
Add dev environment password default 'tinder1'
Refactor Piece#user specs
Add Piece callback create_first_version