Added auto_namespace param to Entity.to_xml() to improve serialization performance. Added include_schemalocs param to Entity.to_xml() to give the option of exporting a valid XML document without the xsi:schemaLocation attribute. #163 #161.
Added missing support for pretty parameter. Exception is raised if auto_namespace is False and no/empty ns_dict parameter is passed in
Removed unecessary code when setting all_ns_dict in to_xml(). Whitespace changes
Merge pull request #184 from STIXProject/issue_163

Auto-namespacing and include_schemalocs Fix #161, fix #163