old_contents: /**
   * set cell value and sync it with the bound element, and trigger recalculation on all cell depend to it
   * @param {mixed}   value       value to be inserted into the cell
   * @param {bool}    render      render computed value of it's dependant or not
   */
  cell.prototype.setValue = function(value, render){
      var a;
      this.value          = value;
      this.floatValue     = ($.isNumeric(value)) ? parseFloat(value) : 0;
      this.formattedValue = '';
  
      render = (typeof(render) == 'undefined') ? true : render;
  
      this.setAffected(true);
  
      for(a in this.dependant){
          this.dependant[a].setAffected(true);
      }
  
      this.processDependant(render, true);
  };
new_contents: /**
   * set cell value and sync it with the bound element, and trigger recalculation on all cell depend to it
   * @param {mixed}   value       value to be inserted into the cell
   * @param {bool}    render      render computed value of it's dependant or not
   */
  cell.prototype.setValue = function(value, render){
      this.value          = ($.isNumeric(value)) ? parseFloat(value) : value;
      this.formattedValue = '';
  
      render = (typeof(render) == 'undefined') ? true : render;
  
      this.setAffected(true);
  
      for(var a in this.dependant){
          this.dependant[a].setAffected(true);
      }
  
      this.processDependant(render, true);
  };
subject: set value as float if it is numeric