Updates to lodash 4 and safely test isArray

[jonalvarezz]

The current function that test if something is an array was failing for Mongoose 4.5.8, MongoDB 3.2.7, since the test value could be an String:

function isArray (t) {
  !isNaN(t.length)
}

isArray([2, 4, 4]) // true
isArray('something') // true (Should be false)

This changes updates lodash to version 4 and:

• Use lodash isArray
• Replace lodash pick for native JavaScript map
• Selective imports for lodash (reduce final file size)

Let me know if something is missed.