Implemented #291

Added `@approximate` to `<quantity>`
Implemented #301

Issue #301 implemented, changed physfacet mixed content model to
m.mixed.basic.plus.access
Added a.common to agencyname

Implemented #352
Removed @label from <physfacet>

Implemented #356
Removed @rules from physdesc and physdescstructured

Implemented #359
Created a.coverage
Updated @coverage in <physdescstructured>

Replaced attribute definition with ref to separate <define>
Added a.coverage to dao

Completed implementation of #362
Removed descriptivenote from origination

For #357
Removed descriptivenote from repository

For #357
Minor fix to repository

Moved optional address outside of the oneOrMore. address shouldn't
repeat in repository.
agencyname now oneOrMore

For #245
eventdescription now oneOrMore

Folr #245
souceentry changed from optional to zeroOrMore

For #245
Added persname to repository

For #358
Alphabetized names in repository and origination
Relaxed order of physfacet and dimensions

For #321
Added am.countrycode to maintenanceagency

Implements #353
Restored @base to <relations>

Implements #351
Removed unnecessary <choice> from arrangement