Multiple changes.

- Raise an error if invalid options are passed to the constructor.
- Bugfix: Ensure drop() only removes the specified collection.
- Fix initializer double memory allocation.
- Fix key/data object allocation: make garbage collection safe.
- Move common macros to the global header file.

FossilOrigin-Name: 98d3016bd25921dead39d9c5474712766b56519d575bc8cd960932b3fbc16b69

README.md

@@ -340,13 +340,6 @@ information about the build environment, the database environment, and
 the currently connected clients.
 
 
-## TODO
-
-  - Expose more database/collection information to statistics
-  - Support libmdbx multiple values per key DUPSORT via `put`, `get`
-    Enumerators, and a 'value' argument for `delete`.
-
-
 ## Contributing
 
 You can check out the current development source with Mercurial via its