Improve email validation (Issue #1)

[MacFJA]

Should follow the RFC 5322 (http://tools.ietf.org/html/rfc5322#section-3.4)

Return true for: "John Doe" <[email protected]> John <[email protected]> <[email protected]> [email protected]

Return false for: John Doe <[email protected]> [email protected] [email protected]> <[email protected] "John <[email protected]>