Fix #include style issues

Include local headers as "something.h" instead of <something.h>, and
vice versa for system headers.  These locations were found while working
on the includedeps.py script; it is easier to fix them than try to
selectively suppress things in the script.

All changes under linearalgebra are mechanical replacements of
  #include <types/simple.h>
with
  #include "types/simple.h"
Other files contain various fixes.  Removed includes for sysstuff.h,
since it doesn't serve a very useful purpose.

Deleted displacement.c and displacement.h instead of fixing, as they
have not been compiled in a long time.

Change-Id: I06e04c74707621903a1fa79de060e1989b99f042