Feature/doc metadata labels (#130)

* Add schema load util

* Added a sample schema turtle file will be useful for future testing and
tutorials.

* Fixed graph label metadata confusion, was created incorrect subjectOf
edges.

trustgraph-base/trustgraph/knowledge/document.py

@@ -3,12 +3,14 @@ from . defs import *
 from .. schema import Triple, Value
 
 class DigitalDocument:
+
     def __init__(
             self, id, name=None, description=None, copyright_notice=None,
             copyright_holder=None, copyright_year=None, license=None,
             identifier=None,
             publication=None, url=None, keywords=[]
     ):
+
         self.id = id
         self.name = name
         self.description = description
@@ -116,4 +118,3 @@ class DigitalDocument:
                 p=Value(value=URL, is_uri=True),
                 o=Value(value=self.url, is_uri=True)
             ))
-

trustgraph-base/trustgraph/knowledge/publication.py

@@ -67,4 +67,3 @@ class PublicationEvent:
                 s=Value(value=self.id, is_uri=True),
                 p=Value(value=END_DATE, is_uri=True),
                 o=Value(value=self.end_date, is_uri=False)))
-