Adds MetadataWebService curation task
Output policy data to METSRIGHTS only if a policy is effect (by date)

Test cases
1. No date present
2. Start date and end date present
3. Start date only present
4. End date only present
Included date values and effective flag on Context element
[DS-1683] Add spell checker to discovery
Merge pull request #294 from richardrodgers/DS-1647-MDWebService

[DS-1647] Adds MetadataWebService curation task
Merge pull request #309 from terrywbrady/master

DS-1697: Output policy data to METSRIGHTS only if a policy is effect (by date)
Merge pull request #314 from KevinVdV/DS-1683

[DS-1683] Add spell checker to discovery
Revert "Merge pull request #294 from richardrodgers/DS-1647-MDWebService"

This reverts commit d9590e3d6555412e363071fe34f878bcb0e0a972, reversing
changes made to b98637afc7c476e75fcf061a326152b690c696b9.
add missing license header in #314 / DS-1683