Marin Bricq

Added the possibility of generating pre-constructed structures such as tree

**Describe the bug** It appears that sometimes when jumping around, the player gets slightly in the block below, leading to a panic

**Describe the bug** Two kinds of bug which I believe are the same: 1) if one holds the left click, while destroying a block if we move the cursor to...

The red cross seems to not have a correct aspect ratio, depending on the window size it changes and sometimes disappears