Refactored importer to single file iteration

In the old version the importer iterated over the import file three times:

1. Blank nodes
2. Concepts and Collections (`:foo rdf:type skos:{Concept|Collection}` triples)
3. Notes, Relations, Labels, …

We (@christophwiemers and I) refactored it to do only one iteration. We achieved it by remembering triples we don't understand jet and trying it again later.
Some more importer optimizations
Not using stupid generated relations anymore
Merge branch 'master' of github.com:innoq/iqvoc into importer
Added a new logger for STDOUT and Rails.logger default
Added time measurement and mode detailed log output
Fixed multi_logger
Disabling indexes in mysql while importing
Start implementing a simple triple-oriented API for the iQvoc data model
Move some importer logic into Iqvoc::RDFAPI
Use predicate to (optionally) determine the actual relation subclasses in build_from_rdf
add rdf_ prefix in all build_from_rdf methods
Rename object => rdf_object in build_from_rdf
Merge branch 'master' of github.com:innoq/iqvoc
Add idea to gitignore
bumped binding_of_caller
language translations
Fixed "none" language handling

* There is no `nil` or `" "` magic for labels without language anymore. The new consensus is `"none"`.
Merge pull request #165 from wvk/master

Implement simple RDF-ish triple based write API
Fixed language independent /collection uri