catch LookupError from openid creation
add Flask-OldSessions to dependencies
also add Flask-OldSessions to fetch_deps.py

This will allow one to install sagenb completely offline.
finally, modify flask to use the old session cookie interface

this is needed to get openid to work properly.
this should fix #184.
Note: openid also requires account creation to be enabled.
Also limit the range for pytz

Newer versions break sage -t src/sage/all.py on Mac OSX
Add a -s option to dist.sh

This will allow one to repackage sagenb with only the changed
files in sagenb itself.
Otherwise, every time dist.sh is run, it redownloads all the
dependencies all over again. It is waste of time and bandwidth.

With this -s switch, you can avoid redownloading all the
dependencies while packaging sagenb.
Update the version to 0.10.8
Merge pull request #194 from ppurka/issue-184

Fix Issue 184 and update version to 0.10.8