Update participant overview to split participants that do have a point of sale account and those that don't

- Split participants and display them in seperate lists
- Add decorators so that login is now required
- Add possibility to create accounts and grant credits
Set the cost of an order to the price of what is being bought on creation
Implement total drink cost function
Show drinks and accounts on buy drink page

- Include extra information for both the drink and the account
- Filter accounts and drinks bought in the past to the current event so only relevant accounts are shown
- Don't show anything if there are no events (create no form choices)
Fix display error in registration complete page
Don't throw an invalid type exception when someone hasn't bought a drink yet
Use the proper counter so labels actually have a number in their for field
Make a function to return the last event instead of copy/pasting some hardcoded numbers
Add Geany project file to gitignore
Create page for login on point of sale pages etc.
Merge branch 'pointofsale'

Conflicts:
	pointofsale/templates/pointofsale/participants.html
	pointofsale/views.py
Show the participants and drinks in a tabular fashion.

- Add some ordering to the accounts (sort by event, then by first name, then by last name)
- Clean up the code for getting accounts to display in the template
- Change the view from form to template
- Rework the template
Remove the actual form for buying
Change name of "buy drink" view to "sale"
Add functionality for buying a single drink, show error when there are not enough credits left
Allow buying multiple drinks at once
Split the drink buying code from the view code

- Use a RedirectView class instead of the old function
- Clean the old function up and make it use exceptions
- This should make it easier to implement an AJAX method to buying drinks
Make the add credits view class based
Change how the current event is retrieved to The Proper Way(tm)
Add debit csv output

- Outputs debits grouped by person, so first the entrance fee and then the drinks costs of person X
- Outputs in plaintext
- Add link from other PoS pages
- Uses quotes on all text fields except from the field names