Cluster lock fix

pfcount support multi keys

Signed-off-by: NYongyue Sun <abioy.sun@gmail.com>

aof_delayed_fsync was not set to 0 when calling CONFIG RESETSTAT

config tcp-keepalive should be numerical field not bool

The previos attempt to process each client at least once every ten
seconds was not a good idea, because:

1. Usually because of the past min iterations set to 50, you get much
better processing period most of the times.

2. However when there are many clients and a normal setting for
server.hz, the edge case is triggered, and waiting 10 seconds for a
BLPOP that asked for 1 second is not ok.

3. Moreover, because of the high min-itereations limit of 50, when HZ
was set to an high value, the actual behavior was to process a lot of
clients per second.

Also the function checking for timeouts called gettimeofday() at each
iteration which can be costly.

The new implementation will try to process each client once per second,
gets the current time as argument, and does not attempt to process more
than 5 clients per iteration if not needed.

So now:

1. The CPU usage of an idle Redis process is the same or better.
2. The CPU usage of a busy Redis process is the same or better.
3. However a non trivial amount of work may be performed per iteration
when there are many many clients. In this particular case the user may
want to raise the "HZ" value if needed.

Btw with 4000 clients it was still not possible to noticy any actual
latency created by processing 400 clients per second, since the work
performed for each client is pretty small.

The command reports information about the hash table internal state
representing the specified database ID.

This can be used in order to investigate rehashings, memory usage issues
and for other debugging purposes.

The new return value is the number of keys existing, among the ones
specified in the command line, counting the same key multiple times if
given multiple times (and if it exists).

See PR #2667.

GEOHASH, GEOPOS and GEODIST where declared as commands not accepting
keys, so the Redis Cluster redirection did not worked.

Close #2671.

Rationale:

1. The commands look like internals exposed without a real strong use
case.
2. Whatever there is an use case, the client would implement the
commands client side instead of paying RTT just to use a simple to
reimplement library.
3. They add complexity to an otherwise quite straightforward API.

So for now KILLED ;-)

Instead of successive divisions in iteration the new code uses bitwise
magic to interleave / deinterleave two 32bit values into a 64bit one.
All tests still passing and is measurably faster, so worth it.

I'm not a strong believer in multiple syntax for the same stuff, so
now units can be specified only as m, km, ft, mi.

Stack traces produced by Redis on crash are the most useful tool we
have to fix non easily reproducible crashes, or even easily reproducible
ones where the user just posts a bug report and does not collaborate
furhter.

By declaring functions "static" they no longer show up in the stack
trace.

In Redis MULTIWORDCOMMANDNAME are mapped to functions where the command
name is all lowercase: multiwordcommandnameCommand().

If GEOENCODE must be our door to enter the Geocoding implementation
details and do fancy things client side, than return the scores as well
so that we can query the sorted sets directly if we wish to do the same
search multiple times, or want to compute the boxes in the client side
to refine our search needs.

Can't immagine how this is useful in the context of the API exported by
Redis, and we are always in time to add more bloat if needed, later.

The GIS standard and all the major DBs implementing GIS related
functions take coordinates as x,y that is longitude,latitude.
It was a bad start for Redis to do things differently, so even if this
means that existing users of the Geo module will be required to change
their code, Redis now conforms to the standard.

Usually Redis is very backward compatible, but this is not an exception
to this rule, since this is the first Geo implementation entering the
official Redis source code. It is not wise to try to be backward
compatible with code forks... :-)

Close #2637.

It's not needed (anymore) and is not available on Solaris.