Added interface to select() for pipes (also named pipes), and select()
stubs for regular files.
Added timer library in FS that select() is the first customer of.
This is unfinished, but committed anyway to get a new release out to
Al and testers.
names. All system processes can now either use panic() or report() from
libutils, or redefine their own function. Assertions are done via the standard
<assert.h> functionality.