This patch changes the default drawing method of the vector sockets to use a column layout.
This allows more interactive use of nodes and avoids the one or two clicks needed to edit vectors
in the old default component layout.
Developers may still use the component layout by using the SOCK_COMPACT socket flag.
For now, we choose to draw the SSS scale vector of the Principled and SSS nodes in a compact
form because they don't require much interactivity.