@toma / @themetalmystic -- Added support for non _id unique indexes and constraint checks
Merge branch 'support_non_id_unique_indexes' of https://github.com/intentmedia/mongo-java-server
Cleanup bfaf812a78692561e7f54df2178182ab47f62214. Closes #6.
update netty to 4.0.15
add .keep in src/main/resources
fix package of MemoryBackendTest
use slf4j logging formatting feature
improve exception handling

follow-up commit for
  - 3743dc4edccc7e55312c0db00d272cbe02e06798
  - bfaf812a78692561e7f54df2178182ab47f62214
type safety