replace llinfos, lldebugs, etc with new LL_INFOS(), LL_DEBUGS(), etc.

dependency cleanup - removed a lot of unecessary includes

added ability to force uniqueness of LLCopyOnWritePointer
converted more variables to units
added convenience function for unit constants

made LLCopyOnWritePointer enforce write access through write() again
disabled some error checking on release for download builds

removed extra dereference for copy on write pointer
moved copyonwrite mechanism to RecordingBuffers from individual buffer
fixed logic that was leaving scene unfrozen when camera moved during metrics gathering

fixed gcc compile error
made LLCopyOnWritePointer contain an LLPointer, not derive from it
added type trait to control periodicrecording mean value type

default to double precision now
fixed unit conversion logic for LLUnit
renamed LLTrace::Rate to LLTrace::Count and got rid of the old count as it was confusing
some const correctness changes

cleaned up API
samplers are now value types with copy-on-write buffers under the hood
removed coupling with LLThread

reviewed by Rick

ignore-dead-branch