Support Iteratee I/O

[dmanchester]

Some useful references:

• http://mandubian.com/2012/08/27/understanding-play2-iteratees-for-normal-humans/
• http://stackoverflow.com/questions/9858095/how-to-understand-iteratee-in-play2
• http://stackoverflow.com/questions/10177666/cant-understand-iteratee-enumerator-enumeratee-in-play-2-0

[dmanchester]

The above references may still be somewhat relevant to Play applications, but there have been changes in the Play architecture around streaming. Latest information: "Advanced topics for Scala" > "Handling data streams reactively".