initializer list in fs_traversal.h
check if all CAS objects match their name
switch to wrapped hash interface
add P to list of known file suffixes
Merge pull request #263 from reneme/swissknife_scrub

First Approach to a cvmfs_swissknife scrub command

This contains a new cvmfs_swissknife command scrub, that goes through a given repository backend storage to check for possible corruptions.
Currently it detects:

    files with malformed names (xx/yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy[C|X|H|P])
    unknown file name suffixes (other than C, X, H, P)
    symlinks (that are not supposed to be there)
    mismatch between content hash and file name in CAS