Update library stack to support GHC 7.8.3 and Aeson 0.7 (fixes #10)

Bump versions of aeson, array, attoparsec, lens, template-haskell

A few small rewrites were necessary to be compatible with old and new
versions of Aeson.
Merge pull request #19 from iconnect/issue-10

Update library stack to support GHC 7.8.3 and Aeson 0.7 (fixes #10)