JCBC-211: Adding a new CouchbaseProperties class for property management.

This changeset adds a CouchbaseProperties class that centralizes
property management for both file- and code-based properties.

Change-Id: I2f32fcb59460630d4cc250c786535980f3bd5dd2
Reviewed-on: http://review.couchbase.org/23942
Reviewed-by: Matt Ingenthron <matt@couchbase.com>
Reviewed-by: Deepti Dawar <deepti.dawar@globallogic.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>