add missing BuildRequires to contrib/dbsake.spec
fix --log-level option

- incorrect conversion caused this option to essentially be broken
refactor fs/__init__.py into fs/util.py

- this moves all the ctypes logic into a separate module
  and defines all the fincore/uncache logic in util.py
cleanup fs commands to use dbsake.fs.util
[dbsake.fs] skip paths that are not regular files

- affects fincore, uncache commands.
  This change avoids a spurious IOError in case we try to
  open a directory, socket or other device that's not a normal
  file, where mmap or posix_fadvise will surely fail even if
  open() succeeds.
add --version/-V option to dbsake

- makes it easier to identify which version of dbsake is being
  used.
use dbsake.__version__ as setup.py's version

- previously version was hardcoded in setup.py. now it is
  imported from the dbsake package.
add sphinx documentation
add python-setuptools to Requires: in dbsake.spec
cleanup comments in dbsake.fs
bump version to 1.0.1
add command example to docs for every subcommand
rename intro -> getting_started and flesh it out

- added more examples about downloading dbsake and reporting bugs
clean up cross document references