code: function findBrush(alias, showAlert)
      {
          var brushes = sh.vars.discoveredBrushes,
              result = null
              ;
  
          if (brushes == null)
          {
              brushes = {};
  
              // Find all brushes
              for (var brush in sh.brushes)
              {
                  var info = sh.brushes[brush],
                      aliases = info.aliases
                      ;
  
                  if (aliases == null)
                      continue;
  
                  // keep the brush name
                  info.brushName = brush.toLowerCase();
  
                  for (var i = 0; i < aliases.length; i++)
                      brushes[aliases[i]] = brush;
              }
  
              sh.vars.discoveredBrushes = brushes;
          }
  
          result = sh.brushes[brushes[alias]];
  
          if (result == null && showAlert)
              alert(sh.config.strings.noBrush + alias);
  
          return result;
      }
docs: Finds a brush by its alias.
  
  @param {String} alias		Brush alias.
  @param {Boolean} showAlert	Suppresses the alert if false.
  @return {Brush}				Returns bursh constructor if found, null otherwise.