Update datatable.html.twig

Adding delay feature; in some cases when we want to render datatable inside a formWizard or bootstrap tabs we get unexpected duplicity of datatable headers, if we delay rendering a little bit after the formWizard or tabs we can see our datatables as expected.
Update features.html.twig

Adding delay feature
Update Features.php

Adding delay feature
Update datatable.html.twig

Tabulation
Update datatable.html.twig

adding de feature to check datatable duplicity
Merge pull request #46 from celvin/master

Adding delay feature