First draft of adding basho_bench driver

[slfritchie]

Hi, I was curious if you'd consider a basho_bench driver for benchmarking.

Items which might need a bit of rearranging:

• subdirectory names and file names
• license for the b_b driver source
• other?

[zhaohansprt]

any idea with this error when lanuch the basho_benchimark?

[error] The on_load function for module e2qc_nif returned {{badmatch,{error,{bad_lib,"Library version (2.11) not compatible (with 2.4)."}}},[{e2qc_nif,init,0,[{file,...},{...}]},{code_server,'-handle_on_load/4-fun-0-',1,[{...}|...]}]}