Lots of mecha changes and additions.

- Added constructible Phazon parts and circuits to R&D machines
- Added a Phazon construction path
- Nerfed the Phazon greatly
 > equip slots down to 3 from 4
 > step_in up to 2 from 1
 > toxin punch damage greatly nerfed (from ~80 tox damage to ~20 per hit)
 > research levels required increased (materials 7, bluespace 6, power 6, emp 6, data 5)
 > research levels from parts reduced
- Fluffed out the Phazon in general (sounds, descriptions)

- Grammar fixes to mecha construction process - added a bunch of missing periods and articles
- Changed Durand construction to require a super capacitor and phasic scanner instead of advanced ones

- Buffed the exosuit extinguisher (now has 1000 water instead of 200)
- Buffed the exosuit plasma generator (now consumes fuel at half the speed and doesn't burn through masses of plasma in minutes)
- Moved the cable layer tool from medical_tools.dm to tools.dm (why even)

- Buffed Ripley's default armour (brute from 20% to 40%, bomb protection 80% instead of none)
- All Ripley variants now have the same lights_power 7 (from Default Ripley's 6, and Death Ripley's 60 which basically created a fully lit square around it)
- The default Ripley can now be augmented with goliath armour plates, up to 70% brute protection (plates drop if Ripley is killed)
- Goliath-plated Ripleys get a different sprite and examine-description
Fixes duplicate Ripley proc code, moves messages to switch() in Phazon damtype change code
Removes comments from combat.dm and phazon.dm
I accidentally the phasing
Fixes the bug with Gygax/Durand armour welding sprites looping infinitely
I think this needs a changelog
A less gimmicky way of removing the attack message from goliath plates
Goliath plates are now NOBLUDGEON
Merge pull request #5200 from PatchouliKnowledge/Phazons

Lots of mecha changes and additions.