Merge pull request #4 from 2xyo/master

Replace the print statement by the print() function #PEP3105
added the beginning of an ex_02.py script
changed an attribute on MarkingStructureType from self.extension_type_ to self.extensiontype_. fixes #1
Update README.md
Update setup.py
Merge branch 'master' of github.com:STIXProject/python-stix
fixed bugs. added content to ex_02.py
Merge branch 'master' of github.com:bworrell/python-stix
Merge pull request #5 from bworrell/master

fixed bugs. added more content to examples/ex_02.py
fixed issue with xml file. added a from_xml() method to STIXPackage()
Merge pull request #6 from bworrell/master

bug fixes and added a new from_xml() function to STIXPackage()
Use new syntax for Observable constructor
fixed bug where incorrect variable name was referenced
Merge branch 'master' of github.com:STIXProject/python-stix
Merge pull request #7 from bworrell/master

bug fixes in from_dict() methods
added hardcoded namespace definitions to output stix document. changed stix_package root level from STIXType to STIX_Package
initial commit of v1.0_final bindings
removed external schema bindings. modified some stix bindings to import the correct modules
fixed most imports. started to fix the use of our abstract type implementations
made extension classes return etree elements for their extension members. indicator.TestMechanismsType instantiates the correct TestMechanismType implementation by looking at the xsi:type attribute