lib/query: refactor & rework

- Move the lib/query/ stuff up a level into lib/
- Associate directly with the Query object
- Rework the Query object to be C++ rather than mixed with C
- Update all dependencies, tests

lib/mu-container.h

@@ -23,6 +23,8 @@
 #include <glib.h>
 #include <mu-msg.h>
 
+G_BEGIN_DECLS
+
 enum _MuContainerFlag {
 	MU_CONTAINER_FLAG_NONE    = 0,
 	MU_CONTAINER_FLAG_DELETE  = 1 << 0,
@@ -221,4 +223,6 @@ MuContainer* mu_container_sort (MuContainer *c, MuMsgFieldId mfid,
 GHashTable* mu_container_thread_info_hash_new (MuContainer *root_set,
 					       size_t matchnum);
 
+G_END_DECLS
+
 #endif /*__MU_CONTAINER_H__*/