restructuring code and includes of ILWIS Python API for cleaner separation into Python or ILWIS(Qt) related classes and domain of functionality

adjust test due to changes in test files
added FeatureCreationError to python API (removed detour via hash_code() of std::type_info)
fix missing commit on IlwisConnectors repo
disable matplot in test.py
interface changes
added catalog only supporting full Url and return items as tuple to Python API
made __getitem__ returned object dynamically typed via to<class>() cast (not yet for all ilwisobject types)
the extended objects are now added to the mastercatalog for catalog objects ( that are files). This gives a consistent view on how many objects there are in that catalog. else they will be created on demand and that makes it unclear how many objects there actually are
added Catalog to Python API including item-retrieval
Merge remote-tracking branch 'origin/master'
small justifications in domain and range
adjusted test.py
added item-domains
added several ranges
added constructor for itemdomain
added several conversion methods
added domain
added different handling of url
added color-domain. non functional at the moment but it doesnt interfere
converts colors