New path library for dttools.

Moves some old path specific functions from stringtools to the new
namespace. Some cleanup of old functions with tests. Also a new useful
path_absolute function.
Corrects path handling in Chirp.

Chirp now always operates from the root directory.
Fix some bugs with path handling.
Correct errors on Darwin.
Merge pull request #180 from dcbradley/cvmfs-try-local-filesystem

Added cvmfs option try_local_filesystem.
Remove old code.

The code changed the url path to an absolute path. This is done in cfs_reinterpret.
Merge pull request #172 from batrick/chirp-path-bugfix

Chirp path bugfix
Organize/alphabetize headers. Remove some repeats.
Cleanup foremen/workers relations
Foremen do not report their own core and memory stats.

Conflicts:
	work_queue/src/work_queue_worker.c
Foreman reports its own disk total and inuse

Conflicts:
	work_queue/src/work_queue_worker.c