Provide an easier/safer way to manage hsRefCnt subclasses
Replace most vault *IncRef() API functions with hsRef versions
Also use hsRef for the vault functions which "return" lists
Use hsRef for storage of the remaining vault nodes
Add a RefCnt leak debug tracker
Fix leak check race condition, and remove an unintentional circular ref
Unify leak checkers
Make hsRefCnt atomic, and merge with hsAtomicRefCnt
Switch plFormat's accumulator to a plStringStream for better performance
Remove unused pnUtTime functions.
std::chrono-ize hsTimer.
Template-ize hsTimer return values.
Work towards killing TimeGetMs.

Only remaining uses are in pnAsyncCore stuff, and I'm not touching that
until the std::thread merge is figured out.
Always use hsTimer for profile stats.

This fixes the weird flickering and inaccurate numbers that were showing up on Windows.
Merge pull request #418 from dpogue/timer

std::chrono hsTimer
Merge pull request #437 from zrax/hsRef

Clean up ref-counting
Merge pull request #438 from zrax/plFormat_stream

Switch plFormat's accumulator to a plStringStream for better performance