#118 Column masking

[Peter Prib]

The columns mask should be improved to call a clientaction javascript or action to detail displayed content. This would make it easy to implement new functions for example, calling indicator.js or my own javascripts. There may be some options required say, parameters, width/height if graphic or image etc.

Thinking about it, would this architecture lend itself to delivering new data type handling or overrrding datatype handling. For example, I may want to introduce a data type that takes an XLM object applies an XSL transform and present it in a different way. The output may be HTML or a graphical image such as canvas.