Swap `redis` for `ioredis` (this breaks the current implementation) [Adds redis sentinel and cluster support]

Created by: nodesocket

I tried to get everything updated. Note, I bumped the version to 1.0.0 to signify a breaking change.

However, when running the tests, I could not figure out why they are breaking with:

Unhandled rejection SyntaxError: Unexpected token u
    at Object.parse (native)
    at Function.Job.fromData (/Users/justin/Sites/bull/lib/job.js:271:40)
    at /Users/justin/Sites/bull/lib/job.js:39:18
    at tryCatcher (/Users/justin/Sites/bull/node_modules/bluebird/js/main/util.js:26:23)
    at Promise._settlePromiseFromHandler (/Users/justin/Sites/bull/node_modules/bluebird/js/main/promise.js:503:31)
    at Promise._settlePromiseAt (/Users/justin/Sites/bull/node_modules/bluebird/js/main/promise.js:577:18)
    at Promise._settlePromises (/Users/justin/Sites/bull/node_modules/bluebird/js/main/promise.js:693:14)
    at Async._drainQueue (/Users/justin/Sites/bull/node_modules/bluebird/js/main/async.js:123:16)
    at Async._drainQueues (/Users/justin/Sites/bull/node_modules/bluebird/js/main/async.js:133:10)
    at Immediate.Async.drainQueues [as _onImmediate] (/Users/justin/Sites/bull/node_modules/bluebird/js/main/async.js:15:14)
    at processImmediate [as _immediateCallback] (timers.js:367:17)