1024-bit rsa keys,  Darwin,  expiration_days

generate 1024-bit rsa keys,  
do not treat Darwin specially in this respect, as openssl is there anyway, 
decrease expiration_days to an acceptable period.
Increase timeout for live docs

Note: it seems that this setting 'idle_timeout' is only used for live
documentation browser pages, so it should be safe to change it without
affecting users' worksheets' behavior.
Make separate config var for pub timeout

Note: the commit message of the parent of this commit is incorrect. The
timeout variable did control all worksheets, hence this commit.
Rearrange config variable descriptions
Merge pull request #118 from dimpase/patch-2

1024-bit rsa keys,  Darwin,  expiration_days
Version bump to 0.10.5
"Remember me" has never worked and is not linked to anything.
Checked as far back as sage-4.7. Removing.
Adapt to new Flask extension module schema

Naming your Flask extension module "flaskext.foo" is now discouraged in
favor of naming it "flask_foo". To accommodate both styles, Flask 0.8
and higher allows you to import "flask.ext.foo", which will first try
"flask_foo" and then try "flaskext.foo". We should do this for all our
flask extension imports.

In the short term, this allows sagenb to build against the latest
version of Flask-AutoIndex, i.e. it deals with the following commit:
https://github.com/sublee/flask-autoindex/commit/2138855d69a124cdaad
Merge pull request #148 from ppurka/rm_remember

"Remember me" has never worked and is not linked to anything.
Merge pull request #149 from kini/flaskext

Adapt to new Flask extension module schema
pub_timeout is useless

Thanks to @ppurka for pointing out that published worksheets are never
interactive anyway.
add options for live documentation timeout to the notebook command
leave doc_timeout to the default value from server_conf.py
increase timeout for live documents to 600s
Merge pull request #1 from ppurka/livedoc_timeout

add options for live documentation timeout to the notebook command
Merge pull request #147 from kini/livedoc_timeout

Increase timeout for live docs
Add a changelog file to record major changes
Merge pull request #151 from ppurka/changelog

Add a changelog file to record major changes
Make flask_version a submodule of sagenb

This is necessary to install sagenb as a standard python library
in site-packages.
fix for SAGE_SRC not being in the environment for classic Sage