Cache: Copyright added, time_stats added
Merge branch 'master' of https://github.com/reverbrain/elliptics into io_stats
Cache: time_stats, json, erase_strategy

- time_stats tree refactored
- cache stats conversion to json added
- cache overflow erase strategy changed to avoid writes or reads on
  keys to be synced.
Cache: timestats refactored
Merge branch 'master' of https://github.com/reverbrain/elliptics into io_stats

Conflicts:
	cache/cache.cpp
	monitor/statistics.cpp

Cache: merge with master
Cache: timers replaced with time_stats
Cache: compilation on gcc4.4 fixed
Cache: Bug with erase in lifecheck fixed
Cache: memory corruption fixed
Cache: Copy of data before sync added
Cache: bug with double erase fixed
Cache: deadlock fixed
Merge branch 'master' of https://github.com/reverbrain/elliptics into io_stats
Cache: monitoring max_depth added
Cache: time_stats doxygen documentation added
Added forgotten doc/Doxy*.in files
Cache: time_stats docs prettified
Cache: Monitoring example added
Cache: Actions set added.
Cache: Static variables replaced with extern