Added extra greek forms 'ϊΐϋΰ'

Also fixed formatting for some of the other characters to comply with the rest of the code.

filtering/type-based/accent-neutralise.js

@@ -40,11 +40,11 @@ jQuery.fn.DataTable.ext.type.search.string = function ( data ) {
         typeof data === 'string' ?
             data
                 .replace( /έ/g, 'ε' )
-                .replace( /ύ/g, 'υ')
+                .replace( /[ύϋΰ]/g, 'υ' )
                 .replace( /ό/g, 'ο' )
                 .replace( /ώ/g, 'ω' )
                 .replace( /ά/g, 'α' )
-                .replace( /ί/g, 'ι')
+                .replace( /[ίϊΐ]/g, 'ι' )
                 .replace( /ή/g, 'η' )
                 .replace( /\n/g, ' ' )
                 .replace( /á/g, 'a' )