CCBC-344/CCBC-426: Core settings integration for SSL

- Support for adding SSL options via lcb_cntl()
- Add SSL-related fields to lcb_settings
- Add (currently undocumented) LCB_FORCE_SSL environment variable to
  test behavior
- Add SSL 'protocol context' to lcbio
- bc_cccp, mcserver, and http are SSL aware in that they will select the
  SSL URIs/hosts if enabled

Change-Id: I0ea47e3ab824156e9456391aa60f5f5867086f61
Reviewed-on: http://review.couchbase.org/37339
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Brett Lawson <brett19@gmail.com>