Fix e-mail syntax checker in topanat

[fbastian]

In GitLab by @smoretti on Dec 11, 2017, 12:44

Currently the e-mail syntax checker of topanat only test for something like .@. ("." being anything)

It should test for [\w\.\-]+@[\w\-].[\w]{2,5}

[fbastian]

In GitLab by @smoretti on Dec 11, 2017, 16:15

e.g. 1@1 as e-mail works but should not!

[fbastian]

In GitLab by @smoretti on Dec 13, 2017, 12:06

Doc about ng-pattern to change that:
https://docs.angularjs.org/api/ng/input/input%5Bemail%5D

Examples howto
https://stackoverflow.com/questions/24490668/how-to-validate-email-id-in-angularjs-using-ng-pattern

[fbastian]

In GitLab by @smoretti on Dec 13, 2017, 12:07

To do at the same time than #155