v0.4.1

• Fix bug where initial keys defined in the first parent layer could not be
  overriden by future parent layers
  • I'm not sure how I thought this was fixed in v0.3.6; in the following example, 1 was incorrectly bound to a in c

[a]
[[keys]]
1 = 'a'

[b]
[[keys]]
1 = 'b'

[c]
parent = { a, b }