support new mixins adding (just as sqlalchemy.exc.DontWrapMixin) for using with reportable()
add mock for testing
support templating
support custom headers
Merge branches 'feature/add-mixin', 'feature/custom-headers-support' and 'feature/template-support' into next_release

Conflicts:
	flask_reportable_error.py
	test.py
add a bootstrap to run tests
prevents removal of ReponrtableErrorMixin from mixin set
prepare new deploy