cmfs-tools: add Makefile.am for debugfs.cmfs

Just add debugfs.cmfs/Makefile.am, and corresponding items in
configure.ac and Makefile.am
cmfs-tools: sync cmfs_fs.h to include/cmfs-kernel/cmfs_fs.h

This commit sync include/cmfs-kernel/cmfs_fs.h from kernel code
fs/cmfs/cmfs_fs.h.

Another important change is, in struct cmfs_extent_rec, e_int_clusters
is replaced by e_int_blocks.
cmfs-tools: replace cmfs_extent_rec e_leaf_clusters by e_leaf_blocks

In OCFS2, all children leaves size is counted by e_int_clusters. In
CMFS, it is replaced by e_int_blocks. This commit contains the data
structure change and relevant changes in other source code files.
cmfs-tools: first commit for debugfs.cmfs

This is the first commit for debugfs.cmfs tool. Currently only command
interface works, help information can be displayed by 'help' or '?'.

This is the compiling passed code base fo debugfs.cmfs. More patches in
feature will make this tool more functional.