Docs, better platform detection

  @belhorn_property

  def CC(self):

    return self.platform.CC

  @belhorn_property

  def platform(self):

    p = detect_platform()

    announce_platform(p)

    return p

class Platform(object):

  CC = None

  name = None

class Mac(Platform):

  name = "Mac OS X"

  CC = which("c++")

class Linux(Platform):

  name = "Linux"

  CC = which("CC")

def detect_platform():

  if platform.system() == 'Linux':

      return self._linux_cc()

    return Linux()

  else:

      return self._mac_cc()

  def _linux_cc(self):

    return which("CC")

    return Mac()

  def _mac_cc(self):

    return which("c++")

def announce_platform(p):

  log.info("Platform... %s" % p.name)

Paratosthenes

=============

Parallel Sieve of Eratosthenes.