Update README with actual async callback behavior

See issue #79, thanks to @ewencp.
Fixed typo in README
Use poll() instead of select() inside redisContextWaitReady()

The current select() is limiting in instances where the fd num is > FD_SETSIZE.
Since redisContextWaitReady() only processes a single fd, select would still
fail.

For compatibility reasons I have converted select() over to poll(), eliminating
this problem.
async: support for determining monitor mode, if so, repush replies callback in expectation of another reply.
Merge pull request #112 from nessence/master

MONITOR causes assertion failure, async.c, line 398.
Merge pull request #101 from ErikDubbelboer/spelling

Fixed typo in README
Spontaneous error reply can always happen
Add ARCH to Makefile CFLAGS / LDFLAGS.

This makes builiding with an optional 32 bit target simpler. For
instance Redis (that contains an embedded copy of hiredis) when compiled
with "make 32bit" uses to pass an ARCH parameter to force an hiredis
32 bit build.
Configurable reader max idle buffer size.

Hiredis used to free unused redisReader buffers bigger than 16k. Now
this limit is configurable (see the documentation updated by this commit)
in order to allow working with big payloads without incurring to speed
penalty.
Max depth of multi-bulk reply moved from 2 to 7.

Hiredis can handle multi bulk replies with a fixed (hardcoded) level of
nesting. This should be changed in the future in order to avoid
hardcoded limits. As a quick fix this commit moves the max nesting from 2
to 7, so that there are no problems when processing replies from the SLOWLOG
command, from Redis Sentinel, or generated by Redis Lua Scripts (that are
allowed to generate replies with any level of nesting).
On stack buffer to read replies set to 16k (was 2k).

It was verified experimentally that this value, on Linux kernels, provides
better performances compared to the 2k value. However larger values
apparently don't produce any noticeable effect on performances.
Test new maximum depth of multi-bulk replies
Mention changes in CHANGELOG
Bump minor version because reader struct changed
make redisConnectWithTimeout connect to 127.0.0.1 instead of 127.0.0.2
Merge pull request #128 from clongeau/master

make redisConnectWithTimeout connect to 127.0.0.1 instead of 127.0.0.2
Try again later for EINTR errors (see issue #99)
Made connect functions return NULL on alloc failures.

Updated documentation and examples accordingly.
Prevent AsyncConnect from crashing on memory allocation failures.
Merge pull request #119 from thefab/fix99

Try again later for EINTR errors (see issue #99)