Added support for 1.13

[evildeeds]

Added support for 1.13 maps; old maps are still supported like before.
Added a few common blocks and missing colors.

Edit: This will close #303 and #307

[evildeeds]

Alright there are only a few things left now;

• some chunks don't load; I suspect they are not even enqueued, but such chunks are rare.
• logging should be redirected to error and log file instead of cout.
• add a lot of blocks to the json palette, I won't prioritize this in this merge.

[evildeeds]

Since early 1.17 is available (21w13a) I did some quick tests to verify if this still works correctly, and it sort of does with the exclusion of missing palette entries and low Y-indexes (deepslate area). Otherwise issues are as stated before as I haven't had the time to resolve them.