removing String to Array conversion while invalidate
datatype and language extraction from XML results is now working correctly
Merge branch 'feature/remoteSparqlEndpoint' of github.com:AKSW/Erfurt into next

Conflicts:
	library/Erfurt/Cache/Frontend/QueryCache.php
Merge branch 'next' of github.com:inspirito/Erfurt into next
Erfurt_Uri::check checks if $uri is a string

before running into a warning or something because
malformed parameter
adaptions on Store and Virtuoso adapter

Store
+ addStatement returns result of backend adapters addStatement
  (its usually a resource)
+ add checkGraphUri to check the given graph uri and throw an
  exception, if there is something odd
+ add checkGraphUri call into deleteMatchingStatements
+ deleteMatchingStatements behavior really differs from
  Virtuoso-adapters one! Problem is, that it does not really
  use the given SPO parameter as pattern, but use only the
  last set one. Means, that for instance the subject and
  predicate parameter are set, only the predicate will be
  use in the SPARQL query later on, which is kinda wrong and
  leads to an invalid and unknown behavior. From now on, it
  will acts like the deleteMatchingStatements of Virtuoso-
  adapter!
+ move validateObject from Virtuoso adapter to Store and made
  it static to be able to use it in other classes like Virtuoso
  adapter

Virtuoso adapter
+ rename _checkModelParameter to checkGraphUri

Store-Adapter-Interface
+ add countWhereMatches function