Change block drop handling to be more vanilla-ish

[minecraft552]

Fixes #41 I have tested this change in the following ways:

• /summon tnt (didn't break as usual)
• break in creative with 0 levels: doesn't drop
• break in creative with 100 levels: drops
• break in survival with hand and 0 levels: drops
• break in survival with hand and 100 levels: drops
• break in survival with pickaxe and 0 levels: drops
• break in survival with pickaxe and 100 levels: drops

I'm not sure how else I should test it but it seems to work just fine.

[bl4ckscor3]

I did a similar change in the port to 1.20.5/6.

[minecraft552]

Didn't realize, sorry.

[bl4ckscor3]

No worries, though the comment was just meant as extra info.