Please provide an initializer with options

I want to inherit and pass other options, which is kind of a pain with the current implementation

``` Ruby
def initialize(key, options={})
      super(key, options[:timeout] || DistributedMutex::DEFAULT_TIMEOUT, options[:exception] || DistributedMutex::DEFAULT_EXCEPTION_ON_TIMEOUT)
      @options = options
    end
    end
```
