Add transactions for import

closes #837
- added transaction handling for import
- added transactions to model functions
- added simple tests for failing imports
Improved Password Reset Tool

Closes #1471

- add api and User model methods for generating and validating tokens
- add routes and handlers for reset password pages
- add client styles and views for reset password form
- some basic integration tests for User model methods
Merge pull request #1415 from sebgie/import-transaction

Add transactions for import
Make it possible to require ghost as a module. fixes #1326
Merge pull request #1521 from hswolff/ghost-as-a-module

Ghost as a module, fixes #1326
Merge pull request #1534 from jgable/passwordReset

Improved Password Reset Tool