• convert structs to classes: uri, urn, uri-ftp, uri-file, uri-http, uri-https, uri-ldap, uri-ldaps
• use closer-mop for defclass
• manually added uri-p, urn-p, uri-file-p, uri-ftp-p, uri-http-p, uri-https-p, uri-ldap-p, uri-ldaps-p
• remove %make-uri, %make-urn, %make-uri-ftp, %make-uri-file, %make-uri-ftp since its only used once respectively
• add/updated constructors: make-basic-uri, make-urn, make-uri-file, make-uri-ftp, make-uri-http, make-uri-https, make-uri-ldap, make-uri-ldaps
• add type declarations to changed functions

Questions:

• The tests are succeeding. Should more tests be added (e.g. with change-class?)?
• Most slots are initialized to nil, to avoid unbound slot error.
  Is that desirable?
• should most slots have an accessor or reader only?
• urn nid and nss are not typed
  (was not sure if they are string only or also other types allowed)

#58 @genworks