It fixes a bad bug that crashes the server in certain conditions
as shown in issue #2210.

Related to #2094.

People mostly use SORT against lists, but our prior
behavior was pretending lists were an unordered bag
requiring a forced-sort when no sort was requested.

We can just use the native list ordering to ensure
consistency across replicaion and scripting calls.

Closes #2079
Closes #545 (again)

status command currently reports success when redis has crashed and the pid file still exists. Changing to check the actual process is running.

Fix function prototype in redis-cli.c.

    if redis works in cluster-mode and redis-cli was run with argv, reconnect if needs.
    example:
    ./redis-cli set foo bar

    if return is MOVED redis-cli just do nothing.

Fix two typos in redis.conf:

- "trnasfers" --> "transfers"
- "enalbed" --> "enabled"

10000 completes in a too short time and may easily provide unreliable
figures because of tiny duration.

bulk_data field size was not removed from the count. It is not possible
to declare it simply as 'char bulk_data[]' since the structure is nested
into another structure.

Improved getting pid

See https://sourceware.org/glibc/wiki/Release/2.20#Packaging_Changes

```sh
$ ~ pidof redis-server
# nothing

$ ~ ps aux | grep [r]edis
redis      593  0.0  0.0  36900  5564 ?        Ssl  Dec02   1:37 /usr/bin/redis-server 127.0.0.1:6379
klay     15927  0.0  0.0  16772  6068 pts/6    S+   13:58   0:00 redis-cli

$ ~ uname -a
Linux edge 3.17.4-1-ARCH #1 SMP PREEMPT Fri Nov 21 21:14:42 CET 2014 x86_64 GNU/Linux
```

This allows shell pipes to correctly end redis-cli.

Ref #2066

Thanks to @badboy for the help in checking the build after the fix.

Track bandwidth used by clients and replication (but diskless
replication is not tracked since the actual transfer happens in the
child process).

This includes a refactoring that makes tracking new instantaneous
metrics simpler.

Closes issue #1935.

Ref: issue #2175

PFCOUNT is technically speaking a write command, since the cached value
of the HLL is exposed in the data structure (design error, mea culpa), and
can be modified by PFCOUNT.

However if we flag PFCOUNT as "w", read only slaves can't execute the
command, which is a problem since there are environments where slaves
are used to scale PFCOUNT reads.

Nor it is possible to just prevent PFCOUNT to modify the data structure
in slaves, since without the cache we lose too much efficiency.

So while this commit allows slaves to create a temporary inconsistency
(the strings representing the HLLs in the master and slave can be
different in certain moments) it is actually harmless.

In the long run this should be probably fixed by turning the HLL into a
more opaque representation, for example by storing the cached value in
the part of the string which is not exposed (this should be possible
with SDS strings).

start_server now uses return value from Tcl exec to get the server pid,
however this introduces errors that depend from timing: a lot of the
testing code base assumed the server to be actually up and running when
server_start returns.

So the old code that waits to see the pid in the log file was restored.