Add an explicit version property to Request as it's set in index.php anyway.
Allow logging in using the OAuth password grant.

This is an initial commit. Tidy up required.
Add configuration

The config.php file is a sibling to database.php and currently holds the
list of client ids that we allow to authenticate with the password grant
type.
Refactor createAccessTokenFromPassword()

Split up what it does into separate methods and also tidy up some
whitespace issue in this file.
adding some friendlier error messages when required fields are missing
allow users to log in on more than one device
Merge branch 'akrabat-web2-login'