allow text-based inputs to handle "multiple"

Several types of input fields have not been handling the "multiple" attribute.  This attribute causes the fields to store their values as an array instead of as a string.  But this fields expect a string when they attempt to load a value from the database.  As a result, the field displays no value.  The "multiple" attribute is needed at least for textarea and email so that validation can anticipate multiple values.  This solution stops the addition of '[]' to the input field's name if it belongs to one of these text-based field types.