no bcc if None
- support more EMAIL_HOST_* params, so that we have more flexibilility using various outgoing email servers
- send all invite emails reusing one connection.
fix broken links when NB is embedded in HTML doc
use absolute links no matter what
Cookie now set by default on root path

This fixes the issue with users having to sign in for each HTML document separately.
Updated model and python files to support new password strategy
Changed password reminder to password reset
Less references to 'password'
User creation forms should respect use of 'set_password' to update the password.
Transactional update script added. Can be run via 'make upgrade'
More changes with user settings.
msg_invite updated
Merge pull request #159 from Eyas/secure-auth

Secure Authentication in Master
fix UnicodeEncodeError
fix instructions: password reminder -> password reset instructions