operation timeout

[wandenberg]

This is the same pull request as #329, just rebased (I'll close the old one)

Add a timeout to read socket to be possible stop the process when the server is taking too long to answer due to high load or a heavy query

[swistaczek]

👍 @wandenberg but Travis builds fail

[arthurnn]

@wandenberg thanks for the PR, do you mind squashing the commits in one, and add a changelog entry?

@durran @estolfo can you guys have a look, does this make sense?

[wandenberg]

@arthurnn I squashed in three commit because it were originally three different features.
If you want to I can squash in only one, but this way is better to understand what was done

[fbernier]

We use this in production and it does work as expected.

[coveralls]

Coverage decreased (-0.59%) to 93.3% when pulling 1deb6e7 on wandenberg:operation_timeout into 68923e0 on mongoid:master.

[coveralls]

Coverage decreased (-0.06%) to 93.83% when pulling 1deb6e7 on wandenberg:operation_timeout into 68923e0 on mongoid:master.

[coveralls]

Coverage decreased (-0.06%) to 93.83% when pulling 470224c on wandenberg:operation_timeout into 68923e0 on mongoid:master.

[agis]

Any updates on this one? /cc @durran @estolfo