add _.cloneDeep

[wy1009]

add _.cloneDeep function

[coveralls]

Coverage increased (+0.06%) to 96.827% when pulling 4c974f4 on wy1009:master into 5c237a7 on jashkenas:master.

[coveralls]

Coverage increased (+0.06%) to 96.827% when pulling 4c974f4 on wy1009:master into 5c237a7 on jashkenas:master.

[coveralls]

Coverage increased (+0.06%) to 96.827% when pulling 4c974f4 on wy1009:master into 5c237a7 on jashkenas:master.

[coveralls]

Coverage increased (+0.06%) to 96.827% when pulling 4c974f4 on wy1009:master into 5c237a7 on jashkenas:master.

[jgonggrijp]

@wy1009 Thanks for taking the effort to submit a pull request and sorry for the long silence!

I just wanted to remark that you did a really good job. Your tests focus on the important things and the code is short and conventional.

I think this should probably be submitted to Underscore-Contrib, but unfortunately that project is not open to pull requests anymore. I'm looking into a way to blow new life into it, however. @jashkenas let's keep this open in the meanwhile.