• improve mutex support (with support for boost::shared_mutex and boost::upgrade_mutex)
• add systematic mixing of the hash value provided. This prevents serious degradation of the hash table performance when the hash function provided by the user has poor entropy distribution. The cost in performance is very minimal, and this helps provide reliable performance even with not so good hash functions.
• make the iteration order deterministic by default (can still be made non-deterministic by adding #define PHMAP_NON_DETERMINISTIC 1 before including the header phmap.h (as is done in raw_hash_set_test.cc
• clean and add a couple examples