ARMORY-150 - Review and correct new armoryd code

Made multiple changes in response to code feedback.

-JSON's createlockbox() function now accepts only public keys and
returns a dictionary.
-Modify unit tests to match code changes.
-Added code to the JSON error decorator that specifies the error trace.
-Miscellaneous cleanup.
Merge branch 'devel' of github.com:etotheipi/BitcoinArmory into devel