* perf: validating the node_modules structure to a specified depth
Ref #722
* feat: adding an update boolean property to the install API
BREAKING CHANGE:
Dependencies won't be updated when `update` is `false`.
It doesn't matter what the value of `depth` is.
`depth` is used for specifying how deep should the install
algorithm analize the dependency tree.
Ref #722
* refactor: merge new resolved deps with the previous