Allow batched command sending

Fixes the issue where we are calling uv_stop in a connection (bad for
multiple connections in a group)
Commands are now sent on the next event loop run instead of the current
one
Update version and version history
Add stacked packet responses
Merge pull request #142 from LinuxJedi/uv_stop

Uv stop
Update version history
Fix memory leak
Merge pull request #144 from LinuxJedi/batch_send

Batch send