CLI interaction with sequence number.

[kuroa-me]

I am having some trouble with using the bbolt cli.

Following the bbolt document, I created a few buckets, each of their key was generated by NextSequence(), then serialized by itob(). Using those buckets in code is perfectly fine, but accessing them with the CLI has a bit problem.

For example, the first bucket key has the byte representation of [0 0 0 0 0 0 0 1], it is quite impossible for me to type that in the CLI and have bbolt convert it back the correct way. e.g.

bbolt keys 00000001 -> [48 48 48 48 48 48 48 49]
bbolt keys \u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0001 -> [117 48 48 48 48 117 48 48 48 48 117 48 48 48 48 117 48 48 48 48 117 48 48 48 48 117 48 48 48 48 117 48 48 48 48 117 48 48 48 49]

Reading from the source code, the cli first read the argv as string, then directly convert them to []byte. And \u0001 being a null character is impossible to type in the cli AFAK. I am attempting to write a PR to solve this in some way, but being a new user of bbolt, I need some advices on the following ideas:

1. try to look for and resolve any \uXXXX in the input, but this would cause some bucket that have \u in their name to have problem with cli.
2. add a optional control flag that only valid for the following 1 [bucket], usage: bolt keys PATH [[-u] [BUCKET]...], that will parse the \u within it or treat it as an sequence number.