Fix for (hash) increment treats long values as int [replaced PR7]

While the (hash) increment() method accepts a long argument (and Redis
HINCRBY/INCRBY/DECRBY treats arguments as 64 bits), it is cast to a
32bits signed int in the JedisConnection class.

 - Removed offensive (& unnecessary) casts

 - Extended integration tests with incrBy, decrBy and hIncrBy to
   demonstrate handling of large numbers

 - Fixed typos in test support
   (CollectionTestParams, AbstractConnectionIntegrationTests)

Issue: DATAREDIS-117