[TASK] Add XML Namespace to templates

It doesnt hurt to deliver some additional comfort to developers.

FT3 extensions are direct dependencies (depending on the selection).
So instead of having the dev to actually add the namespaces, we simply append
it. Deleting stuff is easier than adding.

Fixes #9
Merge pull request #9 from cedricziel/addXmlNsToTemplates

[TASK] Add XML Namespace to templates
[TER] 0.9.0
[TER] 0.10.0