misc: move includes to the top to unhide include errors
stat: speedup statistics update

Remove 3 system calls per update call.
This should greatly speedup startup and somehow improve insert/remove
times.

TODO:
Actually statistics can be moved to separate thread effectively removing
statistics overhead in expense of lower resolution.
blob: switched to adaptive mutexes when available
mobjects: do not leave empty bases on open failures

After hitting open files limit eblob ended up in a loop of creating new
base on each write request that ended up in a failure, so a bunch of
empty bases/indexes were created:

rbtz@storage1b:~$ ls /srv/data/0/|wc -l
43481

Now we should cleanup created files after any kind of an error.

Reported by: agodin@