[FR] Sand / Gravel can fall

[AkmalFairuz]

Describe the feature you want here
Add flag to make sand or gravel can fall , Like WorldEdit on MCPC.

Suggestions
example when //fill -fall, the sand will fall.

Related issues and pull requests
@thebigsmileXD

[inxomnyaa]

Currently to stop it from falling i use an external plugin which disables all block updates, and i have set the block ticking in pocketmine.yml to disabled.
Due to the method MWE2 uses to place those blocks asynchronously, i am unsure if that is easily possible.
Nice request, i will look into it

[inxomnyaa]

Requires new flag implementation