SVGHMI: Input widget overrides undershot() and overshot() methods to display "min: xxx" or "max: xxx" when user input goes out of given range.

SVGHMI: Added clipping to min and max value for all widget using @path,min,max syntax. Added overshot() and undershot() methods to widget base class, called when value is limited to max or min respectively.

SVGHMI: decoupled operation string evaluation from HMI variable uptdate in change_hmi_variable(), paving the way for min/max boundaries enforcement