AdjustmentCurve: added new property-based modes

[klues]

This PR adds a new property operationMode to AdjustmentCurve with the following modes:

• use file and GUI --> original mode, acts as before, is the default operation mode
• use property curvePoints (percent values) --> curve points can be defined by an additional property curvePoints and they are interpreted as percentage of the given min/max range of input and output.
• use property curvePoints (absolute values) --> curve points can be defined by an additional property curvePoints and they are interpreted as absolute values.

The new modes can be handy to rapidly define a simple curve without the GUI and they do not need any external file in bin/ARE/data like the existing mode (which is now called use file and GUI).

updated documentation is still missing and coming.

[klues]

updated documentation with e16988f

[deinhofer]

looks good and very good idea to add properties for easy configuration of curvePoints