1) Defined privilege (see roles.json)
2) Mapped privileges to method access (see authz.json)
3) Extended geni_util method of credential creation to accept CH prvileges
4) User registration now creates credentials with proper privileges
5) Extended defaults.json to add new fields like SLICE_LEAD, SLICE_CERTIFICATE etc.
6) Removed SLICE_URN & PROJECT_URN from unique indexes. This was to allow creating SLICE_MEMBER which has SLICE_URN as its field and hence collide with SLICE Object which has also SLICE_URN as field
7) SLICE creation now generates two entries in database; a) Slice info b) slice_member