added unpause() behavior and changed pause() to do nothing when already stopped

fix for bad values returns from getPeriodMin and getPeriodMax on count stats when no counts recorded
fix for gcc compile time error (typename ftw)

Automated merge with bundle:c:\code\viewer-interesting+c:\users\richard\appdata\local\temp\thg._vi9rd\http__bitbucket.org_lindenlab_viewer-interesting_s1et2g.hg

added flag to LLInstanceTracker to allow multiple values per key
made StatType allow multiple values per key to eliminate block timer related crash

added more MemTrackable types
optimized memory usage of LLTrace some more