[patch] make ktrdump loop reading the ktr buffers

[Matthew Dillon]

    Committed!  Plus I did even more work on the code.  I made it work
    with -s, added a usleep() in the loop, revamped the indexing code
    even more, and made -a work better.

    When I wrote the code originally I tried to mask the start and end indices
    too early and that created a lot of confusion.  The kernel's write index
    is a full 32 bit integer... the variable is only masked when the kernel
    needs to look up an entry.  I made the ktrdump code do the same thing
    pretty much and that greatly improved its readability.

    (Now happily ktrdump -a -l'ing on my test box!)

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>