Harmonize global keyboardCobntroller() function

[falue]

each and every index.html file should have a "onkeydown" attribute which leads to a function that detects the iframe-depth.

eg. chat in website in browser in window detects the main keyboardController() function in "parent.parent.parent.keyboardController()"

which means a function in tools/general.js is doing that and triggers the main function after program-specific functions are triggered.

function localKeyboardController(event) {
  1. do stuff for this current program, eg. arrowLeft/right for imageviewer
  2. always send event to parent.keyboardController() by:  
  detectIframeDepth().keyboardController(event);  // or so
}

[falue]

related #175