Issue 37 (part 2) Add one partition per key, data locality support for them

I still not sure about this part of the fix. It looks complicated and required code from C*  for token calculations.
CassandraRDDPartitioner will change key 'in' request to a set of '=' request to make calls parallel and local.
A support multiply 'in' operation for composite keys  is a free bonus.
C* support only 'in' for last part of the key ( key1=1 and key2 in (1,2,3)), while driver will accept (key1 in (1,2,3) and key2 (1,2,3)) request and generate 9 (key1 = ? and key2 = ?) requests