[Build] Use the same structure for /build/templates as the repo, so we can very easily use templates

I've used this method for my own components and it rocks IMHO :)
[Build] Use a template for files_strapper.xml and add date and version tags
[Strapper] Add version.php
[Strapper] Use AKEEBASTRAPPER_MEDIATAG in stead of FOF_MEDIATAG
[Strapper] Implement getTag()