Fix #351 - make docsite /core-algorithms not 500

Two issues:
  1. the simplate was trying to import aspen.algorithms.server,
     which no longer exists
  2. since we now default to unicode literals, comparing the
     bytes on the line from website.py to the unicode string 'def '
     was failing; changed to compare to b'def '
Merge pull request #352 from gittip/issue351

Fix #351 - make docsite /core-algorithms not 500