Prov

- Added: Option to show attributes of relations in DOT graph generation
- Added: option to show attributes of nodes in DOT graph representation
- Added: Convenient methods for (de)serialising PROV-JSON (closes 17)
- Fixed: No longer output inferred records in PROV-N and PROV-JSON
- Fixed: Bundles now can have own namespaces
- Fixed: missing return Literal(...)
- Fixed: Error getting the value and datatype of Literal

- Changed: Removed out-dated example_graph()
- Changed: Improved mappings between default Python and XSD data types
- Changed: Removed ProvElement as the inferred record for influence
- Changed: Updated examples (primer, bundles1, bundles2)
- Fixed: Removed the duplicated Bundle definition in PROV_RECORD_TYPES
- Added JSON test files from ProvToolbox and a test for loading these
- Changed: Improved Literal equality test
- Added langtag getter to Literal

- Fixed: Removed the 'activity' attribute from Influence expression
- Fixed: Inferred records couldn't be created when the expected types provided as a list

- Changed: ProvActivity.set_time() can now accept just one argument. It previously sets the time of the missing argument to None.
- Changed: ProvAgent is now eligible for entity arguments and ProvEntity for agent ones
- Fixed: Producing the right PROV-N representation for float values

- Added float data type support for prov.persistence
- Removed ProvCollection class since collections should be instantiated as entities
- Added get_attribute() and get_value() to ProvRecord
- Changed: Check if an attribute's value is a valid QName and return the QName
- Fixed exception rendering graphs with empty records

- Fixed: PROV-N export - top-level bundle -> document
- Fixed: Bug when renaming prefixes