Add PartyIDSource of MIC

Imported from previous forum

[ original email was from Jim Northey - jnorthey@lasalletech.com ]
PartyID roles can now refer to exchanges and clearing houses with FIX 4.4. We need to include an PartyIDSrouce for MICCodes, in addition to BICs that was specified as part of 4.3.

[ original email was from Kevin Houstoun - kevin.houstoun@ssmb.com ]
This has been assigned [PC20030319_5] and will be discussed by the technical committee.

> PartyID roles can now refer to exchanges and clearing houses with FIX 4.4. We need to include an PartyIDSrouce for MICCodes, in addition to BICs that was specified as part of 4.3.
>