Creates a method for removing nested user objects

[jakeoverall]

I wrote a pretty simple method for removing user objects that are nested without having to store the unique $id on the userObject itself. Please consider this pull request as it is a method that can be used frequently.

Thanks,

Jake

[coveralls]

Coverage decreased (-1.57%) when pulling ba45beb on joverall22:master into 3291c73 on firebase:master.

[katowulf]

@joverall22 thanks for submitting this! We really appreciate contributions from the community.

This sort of tool is something that should be included using a decorator pattern or with $extendFactory and is not a core feature that belongs in the API.

Cheers,