vcs extension: fix vcs file status detection

This fixes the following:
  - correct ignore state for directories containing only ignored
    files. (only git and bzr backends)
  - correctly mark as new the contents of untracked directories.
  - auxiliar function _path_contains.
  - small bug in bzr backend status detection.
HACKING: remove part about tabs; ranger uses spaces now
core.fm: removed unnecessary import
core.runner: dont switch to console when using "s" flag
Fixed the sxiv workaround to handle spaces and be more POSIX compliant.
added a rifle hook for better sxiv integration
core.fm: use "basename" instead of "path" in sxiv hook

This allows to pass more arguments before the argument list gets too
long.
Add setting "open_all_images", removing "sxiv_opens_all_images"

this is more general and can be adapted to work with more image viewers.
examples/rifle_sxiv: fix rifle_sxiv with chars like []
move examples to doc/examples
move doc/print_{colors,keys}.py to doc/tools/
setup.py: create a /usr/share/doc/ranger directory
setup.py: added _findall function
manpage: renamed example/ to /usr/share/doc/ranger/
directory: typo
config/commands.py: faster filtering
simplified previous commit
container.directory: fix wrong check for None
container.directory: remove unnecessary refilter()
container.directory: remove "signal" argument for refilter