Improved examples code

as example 
BITPOS mykey 1 0
BITPOS mykey 1 1
has same result (integer) 8,
it's maybe better to change "BITPOS mykey 1 1" to "BITPOS mykey 1 2" will have clearly explain what the START param use for.
Merge pull request #409 from jialechan/patch-1

Improved examples code