Added "Pagerfanta\PagerfantaInterface" to the 'use' section..

Makes my IDE happier, and PHPDOC as well.
Add Finite dependency
Add states & transitions configuration
Simple Finite implementation
Use constant for transition names
Use Finite with Payment as well
Use constant for graph names
Merge pull request #1426 from winzou/state-machine

Use Finite State Machine
Merge pull request #1435 from smarques/pagerfantaInterfaceReference

Added "Pagerfanta\PagerfantaInterface" to the 'use' section..