Syncing XML layout with Admiral von Pedantry [DO NOT USE THIS VERSION AS-IS]

You realise we need to switch to JSON soon anyway, right?

(Also doubles as a partial merge of 2.5.5 content. Version bumped for this reason, but this version won't be published - I'm moving straight on to 2.6.3.0.)
Config re-sync

Seeing as Dave went to the trouble, I'll oblige him.
Now for actual update work - XML first this time

Because screw you conformism.

Part 1 of 2. Extra mods will be added after this pass.
Standard config and IDMap pass

(I had to roll back Logistic Pipes as its Factorization integration isn't working correctly with our version.)
IDMap update
Implemented Endgame and Forestry Extras
Ninja-update to Big Reactors just before publishing

No config changes required