Reconsider directionality of the relationship between Indicator and Campaign

[johnwunder]

In STIX 1.0.1 a Campaign may have zero to many related Indicators. Although this allows the association to exist, it poses challenges in managing large lists of indicators within a campaign component and, in particular, could pose even more challenges when considering how to revise and revoke both campaigns and indicators.

It may make more sense to have an Indicator be able to reference (potentially include using the standard STIX relationship structure, more likely just reference) one or more Campaigns instead of the other way around.

[johnwunder]

This will break backwards compatibility if we remove it from Campaign...will need to address that.

[johnwunder]

This has been merged into the version_1.1 branch but still has an open proposal.

[johnwunder]

Proposal period ended and changes have been addressed, so this issue is resolved.