Issue #46 - Update Nomenclature using non-trademarked wordings where …

…possible

* Issue #46 - Update Nomenclature using non-trademarked wordings where possible

Generally, the following substitutions were made:
- Extensions were renamed from "fido." to "webauth."
- CredentialType "FIDO" was renamed to "ScopedUserCredential"
- "FIDO Authenticators" are now "WebAuth Authenticators"
- "FIDO Credential" and similar are now "Scoped Credential"
- "FIDO method" and similar are now "WebAuth method"
- "FIDO Relying Party" and similar are now just "Relying Party"
- The WebIDL DOM interface is now type "WebAuthentication" and named "webauth"

* Issue #46 - Updates per equalsJeffH & vijaybh