Beginning work.
Refactor to eliminate multiple inheritence.

-Move all XMLEditor methods to JSSObject.
-Move all PolicyEditor methods to Policy
-Move PolicyEditor.__init__() to new()
-Move all ComputerGroupEditor methods to ComputerGroup
-Change JSSObject.update() to handle new objects as well as existing.
-Add JSSGroupObject, move JSSGroupObjectTemplate methods to it.
-Fix inheritence for ComputerGroup, Policy
Update tests to support refactoring.
Add support for keyword arguments to JSSObject.__init__().

- Refactor ComputerGroup, MobileDeviceGroup.
- ComputerGroup tests update.
Move methods from PackageTemplate and PackageEditor to Package.

Adjust to work correctly.
Pylint tests. Change tests to support Package refactor.
Refactor Category to single-inheritence.
Remove XMLEditor and Templates. Fix inheritance for existing objects.
Spelling.
Trying to reformat.
Rename JSSObject.update() to JSSObject.save() to better reflect role.
Pretty up CHANGELOG.
Implement several small improvements.

- Type checking for JSS instance arguments to JSSObject.
- Rename SearchCriteria property ```list_type``` to match other objects.
- Add **kwargs to all remaining new() methods.
Reimplement class TemplateFromFile as JSSObject.from_file.
Reimplement class TemplateFromString as JSSObject.from_string()
Update tests.
Update README and reorganize, rename some tests.
Update setup.py for next release.
Merge branch 'refactor-remove-multiple-inheritence' into development

Conflicts:
	CHANGELOG.md