The function contains/include will cause the _.omit function deal with an array object incorrect

[jhao]

The "contains/include" function in original underscore could deal with array correct, such as ["apple","banana","orange"].
When search a key named "a", the original contains would return -1.
But the underscore.string recover the contains, and make the value of return is 0, since it only use the follow function to make it to string simply.
return '' + object; in module.exports