Use latest library dependencies

Full change log:
Use latest scalding, algebird, and bijection versions: #255
Use new Travis CI container infrastructure: #254
Add hook for CAS based memcache mergeable: #252
Bump bijection/algebird versions: #253
Remove + operator: #21
Memcache mergeable - use semigroup: #251
add logic for replicating writes and reads to stores: #20
bump finagle and util to 6.22.0: #247
Minified kill 2.9.3: #249
Read through store - do not query backing store when no cache miss: #246
implementation of store that uses http protocol: #241
Retry unittest: #240
Added endpoint support to storehaus-dynamodb: #236
Https sonatype: #237