Delete a couple of ghost files that were in the tree but not part
of the project (I accidentally added them to CMakeLists while
merging, but they're broken and not part of the Peerplays code), and
add several files that got dropped from the build during merge.
The ID types, object_id and object_id_type, were defined in the db
library, and the protocol library depends on db to get these types.
Technically, the ID types are defined by the protocol and used by the
database, and not vice versa. Therefore these types should be in the
protocol library, and db should depend on protocol to get them.
This commit makes it so.
