Made arch/arch.hpp not include arch/io/network.hpp.
Made some adjustments to headers, to reduce inclusion.
Merge branch 'next' into sam_compilespeed
Merge branch 'next' into sam_compilespeed

Conflicts:
	src/memcached/tcp_conn.cc
Merge branch 'next' into sam_compilespeed
Renamed some stray uuid_t's to uuid_u.
Made filestat.cc include filestat.hpp with the proper absolute path.
Reduced instantiation of serialization functions in rdb_protocol/protocol.hpp.
Moved implementations from machine_down.hpp to machine_down.cc.
Merge branch 'next' into sam_compilespeed
Removed commented boost_types.hpp inclusion line.
Removed all trace of fsck.
Merge branch 'next' into sam_47
Merge branch 'sam_nofsck' into sam_47
Made the linux_file_t construction API be such that non-open objects are inconstructible by API.  Also removed the method exists() which would have always returned true and was brokenly implemented anyway.