Merge pull request #14 from aju/master

Remove heartbeat for synchronous messages to phantom
Fix potential issue with asynchronous function immediately after synchronous one

There could be the problem that no heartbeat interval was set when sending an
asynchronous function before the previous synchronous function responded.

#12 #14
Replace git dependency with regular npm dependency

After https://github.com/nisaacson/linerstream/pull/4 has been merged
v1.0.4