Supermatter Tweak
- O2 Primary mode now actually works.
- O2 has to be at least 15% (instead of previous 400%, WTF?) of core composition to actually have any effect on the core, considering all remaining gas is N2 (so realistically it's somewhere around 13-14%)
Adds two mwerezak's requests.
pAI submission process change

Attempts  to fix  #6481.

Previously it appears observers would be asked once, and only once, if they wished to become a pAI.
If one closed the configuration window without pressing Submit you'd never get the chance to apply again.

Now asks observers every time someone requests a pAI, similar to posibrains and Dionaea pods.
There is already a built-in ask delay of one minute between such requests and ghosts can decide to opt out for the rest of the round.
Map fixes

Removes duplicate pixel_[xy] settings.
Removes a lone air supply pipe.
Installs a pipe manifold in a mining airlock.
Fix runtime due to processing hydrotray at loc=null
Merge pull request #6490 from GinjaNinja32/hydroponics

Fix runtime due to processing hydrotray at loc=null
Merge pull request #6482 from PsiOmegaDelta/pAI

pAI submission process change
Merge pull request #6487 from PsiOmegaDelta/MapCleanup

Map fixes
Updates synth airlock interface messages
Fixes #6488
Fixes #6503
Fixes #6401
Fixes #6466
Fixes #6495
Fixes #6484
Fixes #6474
Makes species mutation a bit easier.
Fixes #6325
Fix for potential infinite splint farming exploit in previous commit.
Fixes #5451  by stealing JimTheCactus' and VampyrBytes' work - thanks dudes.