The spec described parsing this as a 1-element path but
the implementation parsed it as 2 elements which is probably
a better behavior because it's less surprising. The simple
rule is now "only quoted periods are special".
The AbstractConfigObject.merge() method was wrong; it merged in the
wrong order, which produced incorrect results. But there was a test
verifying that the results were wrong! So it's OK right?
Anyway, fix the test, fix the code, be sure it's crystal clear in spec.
