Fixed #90: Allow for longer email address in Return-Path

[derickr]

RFC 2821 states that the local part may only be 64 characters, but with SRS this often gets violated.

This patch takes PHP's filter_var() email validation regular expression, and extends the allowed length from 64 to 124 for the local part, but only for Return-Path headers.

[eileenmcnaughton]

@agileware-justin does this work with your problem emails?

[agileware-justin]

I tested this change using the two email addresses we recorded as being problematic. Tests as shown below passed.

    public function testLongReturnPath1()
    {
        $mail = new ezcMail();
        $mail->returnPath = new ezcMailAddress( "SRS0=3Ypr33=QM=crm.nothappyjohn.org.au=bounce+b.25211.6039846.eb7e7e8ba282f9d0@airquotes.com.au" );
        $this->assertEquals( "SRS0=3Ypr33=QM=crm.nothappyjohn.org.au=bounce+b.25211.6039846.eb7e7e8ba282f9d0@airquotes.com.au", $mail->returnPath->email );
    }

    public function testLongReturnPath2()
    {
        $mail = new ezcMail();
        $mail->returnPath = new ezcMailAddress( "x2108-arfsfufwyfgkvni2x7ww5wvac3eifc2wx3vr1fcwbbysieqppis4ytnyip09xcohck9s1vrm77nbg4xh431tthdsmtmfvfpa@rspf.mxthunderstruck.net" );
        $this->assertEquals( "x2108-arfsfufwyfgkvni2x7ww5wvac3eifc2wx3vr1fcwbbysieqppis4ytnyip09xcohck9s1vrm77nbg4xh431tthdsmtmfvfpa@rspf.mxthunderstruck.net", $mail->returnPath->email );
    }

[agileware-justin]

Awesome thanks @derickr and @eileenmcnaughton - that's going to unblock a lot of emails 😄