Extends the designated constructor of ISHPermissionsViewController to include the dataSource

This is needed so that the requests can be configured when determining if these require/allow user prompts. This is important for permission categories for which the permission state depends on the configuration. It also makes sure that permission requests are only created once.
Fixes readme to reflect changed designated constructor
Permission view controller uses appropriate method to determine if user prompt is allowed

Also simplifies that method
Fixes typos
Merge pull request #9 from iosphere/feature/dataSourceOnCreate

Extends the designated constructor of ISHPermissionsViewController