upgrade bufferedstream@1.6.0 for node 0.10

bufferedStream@1.6.0 uses setImmediate rather than process.nextTick due to a change in how nextTick works in node 0.10 this prevents a race condition where the loop is called before IO is ready.
add node 0.10 to travis config

use strings on all versions for consistency
Merge pull request #42 from jeffbski/buffstream-1.6.0

upgrade bufferedstream@1.6.0 for node 0.10