server.py: cannot import HTML_FILE_TMPL

[CaptSolo]

server.py fails because HTML_FILE_TMPL is defined in build_page.py and not in common.py:

$ python server.py 
Traceback (most recent call last):
  File "server.py", line 6, in <module>
    from common import HTML_FILE_TMPL, DEFAULT_LANG, DEFAULT_PROJECT
ImportError: cannot import name HTML_FILE_TMPL

P.S. it would be helpful to have information about running build_page.py and server.py in the readme doc.