add range-based for_each_pair
Refactor routing plugins:

- remove superflous members from RawRouteData, partially implements #1238
- DescriptorTable moved to BaseDescriptor.h
- added templated assignment c'tor to DescriptorConfig
- refactored check for valid input coordinates, moved to BasePlugin.h
- replaced shared_ptr's to descriptors in ViaRoutePlugin.h with unique_ptr
- implemented FindIncrementalPhantomNode in facades for a single, i.e. first result
- untangled a few includes