Make Long and Double test factories return unique vals

Random was returning the same value multiple times,
causing issues with Set tests
Support hDel with multiple hash keys

DATAREDIS-99
Support lPush with multiple values

DATAREDIS-99
Support rPush with multiple values

DATAREDIS-99
Ignore intermittently failing test until fixed

Should be fixed in DATAREDIS-108
Support sAdd with multiple values

DATAREDIS-99
Support sRem with multiple values

DATAREDIS-99
Verify order of elements in LinkedHashSets
Support zAdd with multiple values

DATAREDIS-99
Support zRem with multiple values

DATAREDIS-99
Add doc on minimally supported Redis version 2.4