Merged requested to merge feature/restructure-type-and-prop-tags into cleanup/next
All properties are defined in a single header dumux/common/properties.hh. This is because property declarations are global in the namespace Properties. In order to simplify forward declarations and overview a single header file is convenient.
New TypeTags for discretizations and physics / models
Removed TypeTag Implicit since implicit and explicit models are no longer different except for the assembler which is set directly in the main file.