Added stix.utils.dates module. Implemented timestamp and idref properties on major components. Resolves #77
Added timestamp attribute to STIXPackage
Added missing stix.utils.dates
Add some fields to Campagin
Fix Hash construction in Example 02. Fixes #76.
Clean up Example 02
Don't try to parse ThreatActorType specific fields if passed an instance of the base type.
Fix bugs related to TTP Resources/Infrastructure not being parsed correctly

Fixes #71.
Whitespace fixes in TTPs
Make python files non-executable
Merge remote-tracking branch 'origin/master' into coa_impl