Stop portable machines updating their icon every atmos tick

[warriorstar-orion]

What Does This PR Do

This PR makes it so that portable atmos machines, notably canisters, spend less time in SSair updating their icons and checking to see whether they should update their icons. Despite all the bookkeeping and flag updating here, update_icon was still getting called and executing countless times, to the tune of 3.5 million times a round:

This removes all that and just calls update_icon when it needs to be called, when we know the appearance needs changing:

• When the portable is connected to a port
• When a tank has been inserted
• When the total pressure in the portable has changed
• When the can is repainted

Why It's Good For The Game

Performance.

Images of changes

Before

After

Testing

Attached canisters to ports, unattached, added tank to canister, removed tank, opened valve, watched light as pressure changed, modified canister paint job.

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Declaration

• I confirm that I either do not require pre-approval for this PR, or I have obtained such approval and have included a screenshot to demonstrate this below.

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Changelog

NPFC

[chuga-git]

oh my god