ACCUMULO-2770 Add utility to read local WAL

Forward port the upgrade code from 1.5.x into a separate utility so
that a user can still read local WALs if they happen to be around.

Recreate LogFile{Key,Value} in their old packages so that we can still
read the old sequence files that have embedded class names.

Modify the utility to optionally accept values as command line options
instead of searching around in the configuration settings. Testability!

Add a WAL file explicitly generated under 1.4 for testing purposes.

Add documentation to the troubleshooting guide to describe usage.

Recover your logs
After something has gone wrong
Watch your flowers bloom

commit 2db5ce6186e32c451328154b024951cc5090505f
Author: Eric C. Newton <ecn@apache.org>
Date:   Tue Jun 5 13:18:22 2012 +0000