Test handle creation for unnecessary handle ID reuse.
Aim to give previously unused IDs to new Kunquat handles.
Test handle creation after creating and destroying handles with all possible IDs.
Resolve device key type more cleanly inside a single function.
Fix some comments.
Fix more comments.
End all json keys with .json.
Rename sample map to note map.
Fix typo.
Remove checks of obsolete key suffixes.
Merge pull request #93 from kagu/json_keys2

End all json keys with .json
Merge pull request #94 from kagu/fix_handle_ids2

Give unused IDs to new Kunquat handles if possible