Wrapped gSettings and the global objects returned by Settings::get() and
Globals::get() in AIThreadSafe, forcing thread-safe access.
This solves the problem of possible corruption of the various LevelMap's
in LLError::Settings due to thread unsafe accesses.
Added LLObjectList::getAvatar(LLUUID) for type-safe and quicker lookup
Added F32 overload to LLSD because using F64 needlessly is silly.
(And its lack of F32 overload caused issues with LLCachedControl<F32>)