Lose access to part testing parts when unlocking node/can build vessels with locked parts

[magico13]

This is partially intentional and the fix is pretty easy: just check if the tech required for each part is unlocked and don't let them build it if it isn't. The hard part is making it so you can still do part testing after beginning research on a node with part testing parts in it. I somehow need to make those parts still be "experimentally unlocked", then I can fix the issue with building vessels with locked parts.

I haven't actually looked into this much because it hasn't been a big priority. If it's an easy fix, it'll be in 1.1, otherwise I'll throw it in at some later time.

[magico13]

I have an idea of how to handle this. I'm pretty sure there's an event for when a tech node is about to be purchased (instead of what I use for after it is purchased) where I can get a copy of the tech node before being unlocked. Then, when I manually lock the node I can do so by applying the copied node instead of just setting it to locked, which might preserve the "experimental" status of the part. If that works it'd be easy to implement and could be done for 1.1