Update PlancakeEmailParser.php

Added three new functions: `getFrom()`, `getFromName()` and `getFromAddress()`
They can be used to return the sender's display name and e-mail address.

Example:
```
$emailParser = new PlancakeEmailParser($email);

$emailFrom = $emailParser->getFrom();
$emailFromName = $emailParser->getFromName();
$emailFromAddress = $emailParser->getFromAddress();
```

Output:
`$emailFrom`: `"John Doe" <john.doe@foo.com>`
`$emailFromName`: `John Doe`
`$emailFromAddress`: `john.doe@foo.com`