decoration time order checking for auth decorators like admin_required

If you sloppily added an `@auth.admin_required` decorator above the
`@app.route(...)` lines you would notice that the permission is not
checked.

The reason for this is that the `@app.route(...)` decorator registers
the view function as is "from bottom up to the route decorator and not
further" in `app.view_functions`.

This commit introduces checks which are performed once at decoration
time to check if the passed in function is already part of the
`app.view_functions` and the permission logic would be skipped.
If this is the case a SyntaxError is raised notifying the developer.
Minor change
make announcements closable
remember closed state in sessionStorage
announcement shown by default and hidden by javascript if closed before
removed unused variable that minification complains about
lessification and coffeefication as requested
Merge pull request #153 from joernhees/closable_announcements

make announcements closable
Using getItem and setItem for sessionStorage
Added support for remember me during sign in
Added announcement related stuff to util.coffee
refactor decorator order guard code into helper
Merge pull request #149 from joernhees/security_check_auth_decorator_order

decoration time order checking for auth decorators like admin_required
Merge pull request #155 from lipis/remember_me

Added support for remember me during sign in
Minor changes
Clean up choices iteration
Updated varaibles for choices iteration
Merge pull request #156 from topless/patch-1

Clean up choices iteration
Now used flask-oauth v0.13 from GitHub.
Merge pull request #157 from gmist/increase_flask_oauth

Now used flask-oauth v0.13 from GitHub