Revert "Rewrite i686 entry point in Rust"

This reverts commit 57b969de31a161269c8496064db98e68e987edae.
Revert "Allow dead_code in main.rs"

This reverts commit 263fc23fcf3f89b68183f36ba7bd6e49f14a6891.
Revert "Poorly rewrite kernel_main in rust"

This reverts commit 17a141781474dcfcd741c179a1dc58550c2853eb.

Conflicts:
	Makefile
	kernel/main.rs