fix XMLSource issue in mappings wiki.
Mappings wiki MW is very old and does not include the <ns> element in it's schema.
Issue reported by [1] and was caused by #233 (from @nilesh-c)

[1] http://www.mail-archive.com/dbpedia-discussion@lists.sourceforge.net/msg06248.html
Added support for unwrapping templates (a template that refers to one or more other templates by name).
Cleaned up code slightly.
Cleaned up code a little further.
Add possibility to exclude language from import
Merge pull request #250 from dfleischhacker/excludelanguage

Allow to explicitly exclude languages from processing
check if ns exists and require to be the same with wikiTitle
(fix according to comments)
Merge pull request #243 from jimkont/xmlsource

fix XMLSource issue in mappings wiki
Merge pull request #255 from gaurav/feature/unwrapped-self-template

Feature/unwrapped self template
Generate revision-uris dataset with oldid URIs again
Merge pull request #257 from dfleischhacker/revisionuris

Generate revision-uris dataset with oldid URIs again