New grep impl

This is an initial rewrite of the grep command. It still has a couple of things missing, but for the most part it should be close to the posix grep specs. I've tested most of the options and nothing seems totally broken.

Things that are still missing.

- grep-style regex isnt supported yet. Need to rewrite grep-style regex to java/perl regex.
- outputting context lines isnt supported. Need to implement line buffering for this.

commit a7dfab627e573776c95fbcbb748a3a1a15155144
Author: Chris <chris.boertien@gmail.com&gtl
Date:   Sun Apr 12 06:27:54 2009 -0600

    Rewrote grep to a mostly posix-compatible version.
    
    Includes all the major features of gnu grep. Missing a couple
    of features that will be implemented soon.
    
    Signed-off-by: Chris <chris.boertien@gmail.com>

 shell/descriptors/org.jnode.shell.command.xml      |   63 ++-
 .../shell/org/jnode/shell/command/GrepCommand.java |  874 +++++++++++++++++++-
 2 files changed, 895 insertions(+), 42 deletions(-)