Updated docs for next version
Updated tests for next version
Enhanced constructor methods

* Notes objects can be cloned with Notes(notes)
* Notes now -require- a constructor argument (to determine arrow count)
* Chart objects now take a sequence, mapping, or another Chart object
* Chart attributes are coerced to the appropriate types in all cases
* Chart equality is now determined by -just- those attributes
* Simfile objects now take a filename or file-like object
* Simfile construction by string is now done via Simfile.from_string
* Simfile.dirname has been removed for redundancy with Simfile.filename
Updated documentation
Version bump