Lock the streams implementation to Streams2

Uses the readable-stream module, pinned at 1.0.x (Streams2) rather than
the node core stream module. Adds node 0.11 compatablity.

See http://www.nearform.com/nodecrunch/dont-use-nodes-core-stream-module
for more details.
Bump dependency versions

Closes #54
Readme and package.json housekeeping