## Changes
This function could panic when either side of the comparison is a nil or
empty slice. This logic is triggered when comparing the input value to
the output value when calling `dyn.Map`.
## Tests
Unit tests.
## Changes
This change adds the following functions:
* `dyn.Get(value, "foo.bar") -> (dyn.Value, error)`
* `dyn.Set(value, "foo.bar", newValue) -> (dyn.Value, error)`
* `dyn.Map(value, "foo.bar", func) -> (dyn.Value, error)`
And equivalent functions that take a previously constructed `dyn.Path`:
* `dyn.GetByPath(value, dyn.Path) -> (dyn.Value, error)`
* `dyn.SetByPath(value, dyn.Path, newValue) -> (dyn.Value, error)`
* `dyn.MapByPath(value, dyn.Path, func) -> (dyn.Value, error)`
Changes made by the "set" and "map" functions are never reflected in the
input argument; they return new `dyn.Value` instances for all nodes in
the path leading up to the changed value.
## Tests
New unit tests cover all critical paths.
Pieter Noordhuis