Add a new command "bmap" to debugfs which calculates the logical->physical block

Add a new command "bmap" to debugfs which calculates the logical->physical block
mapping for a particular inode.

Fixed a bug in the libext2 library which broke ext2fs_bmap if no inode structre
was passed inside for here.

Fixed bad calling parameters to parse_ulong which broken the -b  and -s
options to debugfs, as well as do_init, and the testb, setb, clearb functions.