Fixed bug when sending long key/value through RPC

The method `Bytes.base64Encode()` encodes the input using `Base64.decode` with `breaklines` option enabled by default. If the input is long enough, the returning value will contain '\n' character which breaks the parser on server side. To reproduce this bug, simply set a key longer than 57 bytes with `KyotoTycoonTsvRpcClient` and try to receive it with `ktremotemgr get`. This pull request is to make that option disabled by default. 

We should also allow user to choose the codec when creating KyotoTycoonTsvRpcClient, and it should be `TsvColumnCodec.NONE` (i.e sending it as is) by default as it saves some HTTP traffic compared to `TsvColumnCodec.Base64`. This is useful when user knows that their keys are always in ASCII.