MetaData and "info" command

[GrizzlT]

It would be beneficial if there existed an info command that could display some stats about data in the intermediary format.

The protocol version, display name and optional note will be stored in a new struct called MetaData. This data will be stored under the field name metadata.

Things I'm thinking about:

• protocol version
• display name (defaults to protocol version if none is set)
• optional note
• amount of blocks and properties (per type)
• healthcheck to make sure there are no gaps in blockstate ids

[GrizzlT]

I can't request changes, but lemme know what you think about my comments. :)