API Compatibility change: rename _remove for DICT & B+TREE into _erase for API uniformization.

doc/API.txt

@@ -27,4 +27,7 @@ V0.2.*: * worker_start takes a 'worker_t' as an additional parameter
         change name of _get_ ## field into _get_at_ ## fields
         Since there is a name collision with other methods
         if a field is named 'str'.
+        * Rename _remove into _erase for dictionary & B+TREE (adding a compatibility layer) for API uniformization.
+        The provided _remove doesn't use an iterator but a 'key', incompatible with the one of array or list.
+        But is like the one provided by the priority queue.