Halo 4 Helmet Size A Big Pieces

Placing multiple "big pieces" here where otherwise separate components can fit on the build plate as single pieces.

There is some redesign to account for orientation and support implications, and this can only make support worse. Also of course removal of defunct pins.

These are all pin and size compatible with the master design at

http://www.thingiverse.com/thing:158120

1) A single piece design for the components backfan + BackBottom
2) A single piece design for the Rear Top + T