IsValidEmail() Improved Regex Pattern

[Huntk23]

Made a slight update to the Regex Pattern to conform more to the rules of RFC 5322 which obsoletes RFC 2822.

I ended up updating the regex pattern because the built in .NET MailAddressParser conforms to RC2822 and did not want to re-implement to conform to RC5322. The supplied regex pattern should match ~99% of valid emails.

More tests have been implemented.

Old regex pattern:

--- Valid Email List ---
True : email@example.com
True : firstname.lastname@example.com
True : email@subdomain.example.com
False : firstname+lastname@example.com
True : email@123.123.123.123
True : email@[123.123.123.123]
True : 1234567890@example.com
True : email@example-one.com
True : _______@example.com
True : email@example.name
True : email@example.museum
True : email@example.co.jp
True : firstname-lastname@example.com

--- Invalid Email List ---
False : plainaddress
False : #@%^%#$@#$@#.com
False : @example.com
False : Joe Smith <email@example.com>
False : email.example.com
False : email@example@example.com
True : .email@example.com
True : email.@example.com
True : email..email@example.com
False : email@example.com (Joe Smith)
False : email@example
True : email@-example.com
False : email@example..com
True : Abc..123@example.com

New regex pattern:

--- Valid Email List ---
True : email@example.com
True : firstname.lastname@example.com
True : email@subdomain.example.com
True : firstname+lastname@example.com
True : email@123.123.123.123
True : email@[123.123.123.123]
True : 1234567890@example.com
True : email@example-one.com
True : _______@example.com
True : email@example.name
True : email@example.museum
True : email@example.co.jp
True : firstname-lastname@example.com

--- Invalid Email List ---
False : plainaddress
False : #@%^%#$@#$@#.com
False : @example.com
False : Joe Smith <email@example.com>
False : email.example.com
False : email@example@example.com
False : .email@example.com
False : email.@example.com
False : email..email@example.com
False : email@example.com (Joe Smith)
False : email@example
False : email@-example.com
False : email@example..com
False : Abc..123@example.com

For curiosities sake;

MailAddress constructor try/catch:

--- Valid Email List ---
True : email@example.com
True : firstname.lastname@example.com
True : email@subdomain.example.com
True : firstname+lastname@example.com
True : email@123.123.123.123
True : email@[123.123.123.123]
True : 1234567890@example.com
True : email@example-one.com
True : _______@example.com
True : email@example.name
True : email@example.museum
True : email@example.co.jp
True : firstname-lastname@example.com

--- Invalid Email List ---
False : plainaddress
False : #@%^%#$@#$@#.com
False : @example.com
True: Joe Smith <email@example.com>
False : email.example.com
False : email@example@example.com
False : .email@example.com
True : email.@example.com
True : email..email@example.com
True : email@example.com (Joe Smith)
True : email@example
True : email@-example.com
True : email@example..com
True : Abc..123@example.com

Fixes #27