0.8.6 Brick variants

Changes:

1. Added block migration system to allow seamless block code changes.
2. Most of the brick blocks (passthrough blocks, intakes, outlets) now have brick variants. (All existing blocks will migrate to refractorybricktier3 variants, since that was the original material for almost all of them.)
3. Changed Cowper Stove multiblock structure to accept any tiered refractory brick variant blocks, since those don't need to deal with the temperatures of firing blast furnace.
4. Changed Smoke Stack multiblock structure to require bottom part (first three levels) to be built from any refractory bricks, since that part usuall recieves ~900 deg gas. Upper part can now be built from any brick variant.

Fixes:

1. Fixed full (cube) network blocks not being able to be rotated freely when placed.
2. Fixed valve's animator ignoring x part of the rotation matrix.