Added app schedule, tools and archive/templatetags; updated settings.

* Added app 'schedule' to provides a more generic schedule page
* Added fake app 'tools' to holds generic utilities
* Moved notice/templatetags to tools/templatetags
* Small change to archive.models.Archive display format
* Added archive/templatetags
* Small update to introduction page
Splited storage function from account.extra

* Splited storage function from account.extra -> tools/storage.py
  - OverwriteStorage
  - file_cleanup
* Updated account.models, archive.models
* Added OverwriteStorage and file_cleanup function to notice.models
Added app schedule.

* Added app schedule, largely based on 'notice' app
* TODO: views and templates
Fixed a problem with OverwriteStorage.

OverwriteStorage should be called as:
FileField(..., storage=OverwriteStorage(),...)
                                       ^^
Added schedule.html template for app 'schedule'.

* added 'schedule.views.ScheduleView'
* added 'schedule.html' template, with 'schedule.css' and 'schedule.js'
* added 'schedule.urls', updated django_skaschool.urls
* added tools/templatetags/dict_utils.py
* converted schedule models to south-based
* removed original 'page/templates/page/program.html', related urls
* updated navbar.html