Supported parameter constraint SHOULD allow vendor specific names

[alabou]

As per NMOS "Manufacturers MAY use their own namespaces to indicate capabilities which are not currently defined within the NMOS namespace (urn:x-nmos:cap:)." IS-11 should allow vendor specific capabilities.

Currently the JSON schema constraints_supported.json and the test suite in test_02_02_03_01 and test_02_02_03_02 are too restrictive, they should allow "^urn:x-nmos:cap:" and "^urn:x-[a-z]+:cap:"