Adds documentation for main view controller and request class

Also fixes the return value in delegate method and removes unused enum value for permission state
Fixes typos
Changed ISHPermissionStateDontAsk -> ISHPermissionStateDoNotAskAgain
Typo fixes and minor code refactorings
Adds paragraph about other frameworks
Improves code formatting in readme
Minor readme edit
Merge pull request #4 from iosphere/documentation/permissionsVC-request

Adds documentation for main view controller and request class