issue 123: changed error output in Win32_service and Win32_QFork to use redisLog. Also fixed a few compiler warnings.

fdapi not properly mapping fstat in config.c, so we ended up invoking CRT version without the rfd->fd translation resulting in the CRT calling exit(). Fixes issue 43.

Everywhere in the Redis code base, maxclients is treated
as an int with (int)maxclients or `maxclients = atoi(source)`,
so let's make maxclients an int.

This fixes a bug where someone could specify a negative maxclients
on startup and it would work (as well as set maxclients very high)
because:

    unsigned int maxclients;
    char *update = "-300";
    maxclients = atoi(update);
    if (maxclients < 1) goto fail;

But, (maxclients < 1) can only catch the case when maxclients
is exactly 0.  maxclients happily sets itself to -300, which isn't
-300, but rather 4294966996, which isn't < 1, so... everything
"worked."

maxclients config parsing checks for the case of < 1, but maxclients
CONFIG SET parsing was checking for case of < 0 (allowing
maxclients to be set to 0).  CONFIG SET parsing is now updated to
match config parsing of < 1.

It's tempting to add a MINIMUM_CLIENTS define, but... I didn't.

These changes were inspired by antirez#356, but this doesn't
fix that issue.

Now CONFIG RESETSTAT makes sure to reset all the fields, and in the
future it will be simpler to avoid missing new fields.

This value needs to be set to zero (in addition to
stat_numcommands) or else people may see
a negative operations per second count after they
run CONFIG RESETSTAT.

Fixes antirez/redis#1577

Added --maxheap flag to control size of memory mapped file created. Heap can now exceed size of physical memory. See long comment in Win32_qfork.cpp about implications of using --maxheap flag.

Removing maxheapgb flag in favor of utilizing existing maxmemory flag. Now honoring maxmemory flag in .conf files. Slightly modified default MMF startup requirements to [phys - min(0.2*phys, 3GB)]

This is especially important since we already have a concept of backlog
(the replication backlog).

In high RPS environments, the default listen backlog is not sufficient, so
giving users the power to configure it is the right approach, especially
since it requires only minor modifications to the code.

There were two problems with the implementation.

1) "save" was not correctly processed when no save point was configured,
   as reported in issue #1416.
2) The way the code checked if an option existed in the "processed"
   dictionary was wrong, as we add the element with as a key associated
   with a NULL value, so dictFetchValue() can't be used to check for
   existance, but dictFind() must be used, that returns NULL only if the
   entry does not exist at all.

CONFIG REWRITE is now wiser and does not touch what it does not
understand inside redis.conf.

Those options will be thrown without this patch:
  include, rename-command, min-slaves-to-write, min-slaves-max-lag,
appendfilename.

With this commit options not explicitly rewritten by CONFIG REWRITE are
not touched at all. These include new options that may not have support
for REWRITE, and other special cases like rename-command and include.

At the end of the file, CONFIG REWRITE adds a comment line that:

    # Generated by CONFIG REWRITE

Followed by the additional config options required. However this was
added again and again at every rewrite in praticular conditions (when a
given set of options change in a given time during the time).

Now if it was alrady encountered, it is not added a second time.

This is especially important for Sentinel that rewrites the config at
every state change.

Fix for issue #59. Generated FDs are used everywhere until a SOCKET handle is used by the Winsock APIs. The win32_socketmap code generates the simulated FDs and handles the mapping from these to socket handles.

This fixes issue #1094.

time_t is always 64bit on recent versions of NetBSD.

This way just after the CONFIG SET enabling the min-slaves feature it is
possible to write to the database without delays.

This feature allows the user to specify the minimum number of
connected replicas having a lag less or equal than the specified
amount of seconds for writes to be accepted.

Should be "continue" and was "return".

This fixes issue #1110