Namespace added

[pdscopes]

Firstly, thank you for writing this brilliant distributed semaphore using Redis!

For me to be able to use this I require a namespace for the RedLock class, which I have added along with some PHPDoc documentation and PHPUnit tests.

[annuh]

Could this PR be merged? I need the namespace support for my project :)

[pdscopes]

You can use my code directly if this doesn't get a merged (doesn't look likely) by add a my repo as a VCS repository to your composer file, i.e.:

{
  "repositories": [
    {
      "type": "vcs",
      "url": "https://github.com/pdscopes/redlock-php"
    }
  ],
  ...
  "require": {
    "ronnylt/redlock-php": "~1.0.0"
  }
}