code: public static String add( String... strings ) {
          int length = 0;
          for ( String str : strings ) {
              if ( str == null ) {
                  continue;
              }
              length += str.length();
          }
          CharBuf builder = CharBuf.createExact( length );
          for ( String str : strings ) {
              if ( str == null ) {
                  continue;
              }
              builder.add( str );
          }
          return builder.toString();
      }
docs: Add many strings together to another
  @param strings strings
  @return new string