Getting value's timestamp

[wision]

Mget doesn't return value's timestamp, which might be a problem for some people.. we deal with it by returning raw data instead of associative array (falsecz@a3d7b8f#diff-50cfa59973c04321b5da0c6da0fdf4feL416).

Considering that this is a breaking change, I'd like to ask, if you plan on making raw output optional or something else in order to return timestamp as well.

[fengmk2]

I think it's good to add a options to decide return raw or value only.

like

function mget(tableName, rows, columns, {raw: true}, callback);

You commits falsecz@a3d7b8f look goods, welcome to merge into here.

[wision]

#63