Allow the profiles to be used to be specified as a delta from the default profile list.
You can now overide :default in your project.clj to change what profiles are active when none are specified. As part of this change, default is no longer used to for built-in settings; these are now stored in the :base profile. This makes it possible to override :default while still including the :base profile.
if a profile value is a vector, then combine the values using combine-profiles. this allows you to remove duplication by putting shared configuration in "base" profiles.
…es like the last :default change.