This is a big change, so please be cautious

- Added: First version of client api access with client user credentials
- Changed: 
  - merged remoting_lib and tform into one new base file where appropriate
  - moved some methods into helper methods
  only those methods remain in remoting_lib or tform that are completely
  different in these files or are only used in one of them
- Changed: added check of _GET array in json api handler