Tasks that are Easy Enough for newcoming programmers

[xoft]

Maybe another category: "tasks that are too easy to do but too boring for me to do"
- Block properties - We need an update on blocks' properties. Specifically, g_BlockIsSnowable[] in BlockID.cpp is missing a few blocks, therefore vines are generated snowed-over. All the BlockID.cpp's boolean block property arrays need checking and also syncing to newest block IDs.
- Item stacking - The max amount of items per single stack needs to be implemented. Currently it has been done for only a few items. cItemHandler::GetMaxStackSize() function