Throw exception when block type is not set

Rather than Fatal Error,

Fixes #174
Improved exception handling

- Improved exception handling (wrap original exception)
- And show the real problem when a template does not exist.
added where not functionality
extracted function for setting where statements
corrected comment ;)
added whereNot to interface
moved const from AbstractListBuilder to ListBuilderInterface
introduced querybuilder as member variable
corrected annotation for querybuilder
corrected annotation for querybuilder
made setWheres protected
changed function name from setWhere to addWhere
introduced temporary node in webspace tree
fixed interface
fixed config
introduced arrayable interface
added toarray function
ADded structure view resolver
Enable content types to add view data

- Enable content types to prepare data explicitly for the view by
  implementing a "getViewData" method.
Readded StructureViewResolver