Ensure results from multiget have the proper bucket type.

Addresses #321.
Update benchmark in multiget for bucket types.
Adjust docs on multiget function
Fix tests for multiget w/bucket-types
Merge pull request #331 from basho/bugfix/sdc/321-multiget-btype

Ensure results from multiget have the proper bucket type.
Make UTF8 search test work provisionally.
Add failing test reproducing #322 on PB.
Handle multivalued fields a bit inelegantly
Use generated keys and limit the queries by those keys.
Extract search query codecs into separate methods.
Encode the query as UTF8 if given as unicode.
Merge pull request #335 from basho/bugfix/sdc/322-pb-multivalued

Resolve multivalued-fields issue
Initial version at testing MR changes for YZ
PEP8