[FIX] isLoginFree -> isLoginAvailable calls
[MIN] DisplayLoginPage setting in sample config
[FIX] SSO Login + some related refactoring
[DEL] Deleted obsolete cache.py
Revert "[DEL] Deleted obsolete cache.py"

This reverts commit 0a0b2a5ea8b5a1a8ebacec8dcb568e6c8fc9f2a1.
[IMP] Revamped old red warnings

Changed the old red warnings for warningMessage boxes in:
* abstract submission: not open, disabled
* registration: disabled
* evaluation: disabled
[MIN] Some PEP8 compliance added
[IMP] Abstract submission start&end date in tpl
[NEW] Added Roboto font
[MIN] Moved typographic rules to typography.css
[FIX] Chat rooms link not showing in conf sidebar
[NEW] Added base template for conf display body
[IMP] Added i18n to SystemLinkData captions
[MIN] Homogenization to SystemLinkData captions
[NEW] Wrapper template class for ConfDisplayBody

Also, author index template updated to match this new approach
[NEW] Style for info message boxes
[NEW] Style for success message box
[IMP] Conf display tpls style updated

* Title fetched from DB
* Homogeneous title style
* New information box for closed/disabled sections
[MIN] New info message box class name changed
[IMP] Style of toolbars in conf display pages