Free event loop.

The capture `#_read` method now is wrapped in a `setImmediate` as it
didn't seem to defer back to the event loop otherwise.
Add replay file.

Also correctly move `#getStats` method to `Live` instead of `Capture`.
Add test NPM command.

Also clean up tests and add mocha as development dependency.
Rename C++ files.

Add NPM clean command.
Add tests to count packet fetches.

It seems that the `dispatch` method isn't actually synchronous (other
calls to `_read` happen while the first is still running).
Switch to old mode streams.
Start conversion to full dispatch batch buffering.
Continue implementing new dispatch logic.

Performance seems to be satisfactory (similar or slightly faster than
the original pcap implementation).
Finish new dispatch implementation.

Also added tests for replay captures. Read and dispatching should now
work as expected.

From running performance tests vs. the original implementation, we
seemed to have kept a similar or even gained a little speed. However our
implementation is potentially too polite (i.e. it becomes much slower
when run alongside the other).
Stop exposing internal PCAP handle.

Also added tests for correctly closing the stream (and the PCAP handle
is now simply freed on the stream's end event).