Gracefully handle Riak disconnects

Previously, Riak CS would not start if it was unable to connect
to Riak. Furthermore, it would eventually crash if it was disconnected to Riak.
This was due to the fact that the `poolboy` workers would die and poolboy would
not try and restart them. This leads to the `poolboy` supervisor eventually
crashing and then it bubbles up to the `riak_cs_sup` crashing. The main
change here is that we pass the `auto_reconnect` option into
`riakc_pb_socket`, which allows it to return from `start_link` even if
it can't connect to Riak. Attempts to use `riakc_pb_socket` when it's in
this state will return `{error, disconnected}`. I've tried to handle as
many of the cases where this might happen, and return 503 to the end
user. There are cases where we might be far enough in the response
(headers already sent over the wire), where for now I just Let It Crash.
Originally, I had thought about adding a 'health' thread that would
monitor Riak availability, for the purposes of informing the deployer
via log messages. However, for now, I think the log messages are clear
enough when Riak gets disconnected that it should be obvious. The sudden
spike in 503 responses should also be a pretty good indicator. Other smaller
changes are detailed below.

* Allow `riak_cs_storage_d` to start even if it can't immediately connect to
Riak
* Refactor `riak_cs_wm_common:forbidden/2` to handle disconnected Riak
when retrieving the user record
do not allow invalid addresses to succeed in parse_ip
Merge branch 'develop' into bugfix/ipv4strict
Merge in 1.3.1 changes
return Error from parse_ip, make pure and add a spec for helper
reformat resurrection code to standards. make check/2 pure
fix unused var warning
refactor riak_cs_utils:create_user/2
remove unnecessary comment
add invalid condition message
add rest of the response info for malformed_policy_condition
add test for bad ip and throw error for malformed_policy_condition
return malformed_policy_condition if secureTransport is not a bool and add a test for it
Merge branch 'refactor/gc' into develop
Merge branch 'bugfix/ipv4strict' into develop
Merge pull request #519 from basho/feature/handle-riak-disconnect

Gracefully handle Riak disconnects
Move basho_bench driver/config to basho_bench repository

https://github.com/basho/basho_bench/pull/78
https://github.com/basho/basho_bench/pull/81
Merge pull request #536 from basho/move-basho-bench-driver-to-bb

Remove bench directory, it is now on basho_bench
Added PHP client tests to Makefile.
Added consistent READMEs to each client library language test directory.
php-tests: fixed to work with aws-sdk-php-2.3.x.  user creation in
running php-test.