python-futures: New package (provides concurrent.futures)

The python-futures package is a backport of Python 3.2+'s
concurrent.futures module to Python 2.6+.

Signed-off-by: Dan McDougall <daniel.mcdougall@liftoffsoftware.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
fbset-modes: Explicitly set MACHINE_ARCH

* bitbake-diffsigs output:
  basehash changed from 2f6aa4302713441e9c3c7207c4edea33 to 3486f2b65998ee4ec5bd5fbbe02cadb0
  List of dependencies for variable TARGET_LD_ARCH changed from 'set([])' to 'set(['TUNE_LDARGS'])'
  List of dependencies for variable TARGET_AS_ARCH changed from 'set([])' to 'set(['TUNE_ASARGS'])'
  List of dependencies for variable TARGET_OS changed from 'set([])' to 'set(['ABIEXTENSION', 'LIBCEXTENSION'])'
  List of dependencies for variable TARGET_CC_ARCH changed from 'set([])' to 'set(['TUNE_CCARGS'])'
  List of dependencies for variable TARGET_ARCH changed from 'set([])' to 'set(['TUNE_ARCH'])'
  Dependency on Variable ABIEXTENSION was removed
  Dependency on Variable TUNE_CCARGS was removed
  Dependency on Variable TUNE_FEATURES_tune-armv5t was removed
  Dependency on Variable TUNE_FEATURES_tune-armv5te was removed
  Dependency on Variable TUNE_ARCH was removed
  Dependency on Variable LIBCEXTENSION was removed
  Dependency on Variable TUNE_FEATURES_tune-armv5 was removed
  Dependency on Variable TUNE_LDARGS was removed
  Dependency on Variable DEFAULTTUNE was removed
  Dependency on Variable TUNE_ASARGS was removed
  Dependency on Variable TUNE_FEATURES was removed
  Variable TARGET_LD_ARCH value changed from 'none' to '${TUNE_LDARGS}'
  Variable TARGET_AS_ARCH value changed from 'none' to '${TUNE_ASARGS}'
  Variable TARGET_OS value changed from 'linux' to 'linux${LIBCEXTENSION}${ABIEXTENSION}'
  Variable TARGET_CC_ARCH value changed from 'none' to '${TUNE_CCARGS}'
  Variable TARGET_ARCH value changed from 'allarch' to '${TUNE_ARCH}'
  Hash for dependent task fbset-modes.bb.do_patch changed from eb8e475b55d64d5c9f6427a90e080ba6 to ee7e89fdd852378ee18ac23cdd92f3d3