* CGameLoader created a new JS::Value when assigning to m_Metadata.
This means it didn't actually update metadata in SavedGames::Load. The
new approach solves this problem and should work well if
CScriptValRooted gets replaced in the future.
* The cloning in ScriptFunctions.cpp was required. Removing it caused
compartment mismatches.
* Now CGameLoader loads the metadata unconditinally because we didn't
actually use the option to not load load it.
Ref #2415
This was SVN commit r15589.