added annotation decorators to all user layer and component classes
fixed up tangle of imports
fixing up unit-tests after introducing annotations
debugging decorator annotations
added resolve_reference decorators to ul object to/from_xml methods
added conversion to SI units from 9ml units
debugged projections.py for new reference resolution
added a test annotation
added annotations to abstraction layer readers and writers
debugged annotation decorator
debugged selection to_xml
Merge pull request #60 from tclose/decorators

Added annotations to (almost) all 9ml elements via decorators
added spec bib
Merge remote-tracking branch 'incf/master' into updated_spec
removed quantity object
implemented value types for property object
fixed imports in user_layer/values.py
fixing up bugs with changes to lib9ml
cleaned up propery from_xml
fixed up test xml formats to match spec