ignore PSR2.Classes.PropertyDeclaration.Multiple

We often declare several properties using the same statement, for
example:

 class Foo {
   public $var, $bah, $temp;
 }

Change-Id: Iaaf725ad848d0ab8823f04890f4d98d00b8a4a24
disable Generic.Strings.UnnecessaryStringConcat.Found

For code prettiness, we do a lot of string concatenation on multiple
lines:

 $foo = "some long string..." .
        "continued there";

This patch disable the rule that detects 'useless' string
concatenations.

Change-Id: Ibab5740bc344731604270d311f1f9cc565a66a1a