Added KSIs to fifo_enforcer.cc.
Made serializer_t::index_write take an exiter parameter.

A weak or fake implementation is used in some places though.
Made the cache not take use of the index_write exit_write_t parameter just yet.
Removed unused functions do_writes and serializer_index_write.
Moved serializer_block_write to translator.cc.
Revert "Made serializer_t::index_write take an exiter parameter."

This reverts commit b746271e42f5d1c7190593139512ef129cdc961d.

Conflicts:

	src/serializer/serializer.cc
	src/serializer/serializer.hpp