Version beta10

Voting will be skipped, if no initiative is admitted for voting

Invite code feature allows people having an invite code to create one account

Contingent system to limit the number of initiatives or text entries to be submitted by each member within a given time

Ability to store a formatting engine for each draft, which can be used to allow initiatives to choose between available wiki parsers

New table setting storing user settings for the frontend (replaced hidden_hints column of beta9)

Better policy support:
- New table allowed_policy to select which policies can be used in each area
- Policies are now ordered by an index field

Bugfixes:
- In function close_voting(...): If there were no voters, this resulted in a NULL value as positive and negative vote counts
- In delete_private_data() function: Secret fields of member table are now deleted too
- Major bug fixed in lf_export, which caused data loss on execution