Add inventory right click drag and drop
Fix GCC reorder warning

Caused by a020d1b653f94fbcaac06c15f9dbab4521fda355.
Make dump's output prettier

Changes:
  * Indentation with tabs by default.
  * Array keys dumped without "[i] = " prefix.
  * String keys that are valid identifiers aren't enclosed in '[""]'.
  * Basic support for multiple references (as specified in the comment).