fixing develop templates layout and deleting unused
removing html templates, adding appropriate jinja2 templates, and changing them

changes in header.jinja2
- showing different menu layout for authenticated users
- adding links to signin, signup, logout pages
- authenticated users have links to their profiles (they don't have
views right now)
adding new views for categories, changes in login/signup views, other changes and fixes in views.py, adding templates.py, changes in __init__.py

changes in views.py:
- views repositioned
- removing dublicate view to home route
- adding __call__ method to all classes:
- - - it is used for check_session function
- fixing all login views
- removing bad_login function
- fixes in singnup view:
- - - it didn't work because of mysqlapi utf8 bug
- - - added for loop to iterate over request parameters
- added edit_category (doesn't work for now, because of some unknown
problem in mysqldb)
- added change_status_category (doesn't work for now, because of some
unknown problem in mysqldb)

changes in __init__.py:
- removed unused routes
- routes repositioned
- added comments to distinguish them easily
adding templates.py and BeforeRender subscriber

sorry for short description, its too late right now…

but main point is that it allows us to have access to methods:
- authenticated_userid (it is used in header.jinja2 to check if user is
authenticated);
- has_permission (it will be used later, when object security will be
implemented);

in our templates, they are accessed using utils (example:
utils.authenticated_userid() )

they are made available via subscriber decorator, which decorates
function, and makes it an event subscriber for the BeforeRender event