reset connection state

[boolka]

When connection was interrupted for some how while executing the query it must be cleaned. Calling connection._connection.reset_state() returns connection back to pool cleaned.

The problem was discussed here #93 and #71

[boolka]

@long2ice pls consider my merge request

[long2ice]

Thanks!

[tiejunhu]

Thanks!

Would you release a new version so that we could update our depends in project from git commit to a version number? Thank you.