GitLab

- If one-lease-per-client is true, release the other lease even if it
  hasn't yet expired.

- Look up hosts by name (from Brian Murrell).
- Make it possible to safely stuff statements into host groups.

- Return ISC_R_NOKEYS when a lookup fails because no keys were provided.

- Allow db_startup to just do a syntax check on the lease file rather
  than actually rewriting it, for the -T flag.

  creates to fail.

- Adjust all the parser prototypes for the New Parsing Regime.

  hanging it off of a host declaration.

- Support parsing of named groups, and use of named groups within host
  declarations.