Automatic disconnection of native client

[wlhjason]

The DB API 2.0 Connection class implements the context manager protocol and closes each cursor upon exit (disconnects each underlying native client).

In contrast, the native Client class does not implement the context manager protocol and seems to expect users to call client.disconnect() when they are done.

Is there any particular reason for this design? If not, could I potentially open a PR to add __enter__ and __exit__ methods to the native Client (along with tests and docs)?

[xzkostyan]

Hi.

There is no particular reason. __enter__ and __exit__ methods will make Client usage more convenient. Please add tests for this feature.

[wlhjason]

@xzkostyan Just opened #238 to implement this.

[wlhjason]

@xzkostyan Thanks for merging and tidying this up!