Changed the behavior of VocabString.lookup_class() to return the VocabString class when the lookup fails
Changed nsparser get_namespaces() logic to play nicer with documents that utilize non-STIX namespaces. Tests fine with the STIX sample documents, but could use some more testing.
Updated nsparser code to detect namespaces on user-defined controlled vocabuarlies. Significant changes to code that walks the python object model to retrieve namespaces and xsi_type attribute values
Merge remote-tracking branch 'origin/vocabs' into vocabs
Updated nsparser to maintain public interfaces. Input schemalocations are attached to a STIX entity on from_xml() call and exported during to_xml() unless overridden by a default.
Updated to_xml() to accept schemaloc_dict parameter which allows users to pass in third-party schemalocations
updated __all__ in stix.bindings.stix_common

Doing "from stix.bindings.stix_common import *" fails due to
nonexistent ContributorsType. Fixed this problem by updating the __all_
list with the current set of Types
Added PackageIntents class to handle issue where invalid types could be passed into package_intents list
Updated Indicator.indicator_types to use IndicatorTypes entitylist
Set indicator_types property to IndicatorTypes instance by default
Fixed potential issue with namespace parser not descending into VocabString EntityLists in STIXHeader and Indicator
Added VocabString EntityLists for Incident class
Added Roles VocabString EntityList impl to InformationSource
Added VocabString EntityLists to TTP classes and modules
Merge pull request #167 from chongkim/stix_common_export

updated __all__ in stix.bindings.stix_common
Merge remote-tracking branch 'origin/master' into vocabs
Added sample demonstrating VocabString use.
Added examples section to documentation
Merge pull request #168 from STIXProject/vocabs

Controlled Vocabularies
Updated examples in docs to mention python-cybox set_id_namespace() method