code: function( input, type, charset ) {
  
      type = ( type || 'Q' ).toUpperCase()
      charset = ( charset || 'utf-8' ).toUpperCase()
  
      if( type === 'B' ) {
        input = this.encodeBase64( input, charset )
      }
  
      input = this.encodeQP( input, true )
      input = [ charset, type, input ].join( '?' )
  
      return '=?' + input + '?='
  
    }
docs: Encodes a string into mime encoded word format.
  <http://en.wikipedia.org/wiki/MIME#Encoded-Word>
  
  @param  {String} input
  @param  {String} type
  @param  {String} charset
  @return {String}