Added PHP client tests to Makefile.
Added consistent READMEs to each client library language test directory.
Added note to disable unicode detection on installation of Composer.
Don't require editing of `test_services.json`

9feb8957b35950291f7972d3e6896681e65031c2 no longer requires you to edit
`test_services.json`, because it creates a user for you. You still
need to edit it if you're running Riak CS on something other than
localhost:8080
No longer require editing on `s3.yml`

This step is no longer required to run the tests
Removed note about issues with PHP 5.3.x because of the earlier note
suggesting 5.4.x.
Merge pull request #539 from basho/hc-client-library-test-docs

Added READMEs to each language client library test