Merge changes commited to 1-open-source-license into master

See merge request !6

Added compability for OpenSUSE 42.3 including cmake as low as 3.5.2 and fixed wording in license sections.

Resolve "Open source license"

Closes #7 and #1

See merge request !5

Added LGPLv3 information, added hykops_rudder to the build, merged splitted source files, removed obsolete files, and improved the makefile system for parallel builds on linux.

Closes #4 and #2

See merge request !4

The compilation and execution of libraries and binaries with shared and static libraries has succeeded on Windows 11, OpenSUSE 15.2 and Debian 11.

Closes #4

See merge request !3

Fixed order of additional options required for Windows and added an interface target to facilitate linking.

Adjusted further std::map::insert operations to comply with the logic from QMap, the code once was based on.

Erased std::map entries if a new one is to be inserted, because that is what QMap::insert does. Direct change to insert_or_assign is only possible staring from C++17.

Splitted implementation and defition of mapkeys, and ensure compilation of targets using HYKOPS with C++11 to 20.

Adjusted ranges for for-loops in lofttobsplinesurface to avoid segmenation faults caused by the original design while creating almost idential surfaces

Link HYKOPS library with Boost library, corrected ranges for the loops in AssembleFactory::lofttobsplinesurface and other fixes

Resolve: Change to CMake build system

See merge request !1

Configured CMakeLists.txt s.t. HYKOPS may be found with cmake in an external project using find_package(HYKOPS)

created a working cmake setup to compile hykops and added a Doxyfile for autogenerated documentation with doxygen

Freed hykops_propeller from Qt. The C interface has not yet been converted. Not tested but compiling.

Conforming parsing and serialization interfaces for the HYKOPS framework - but not yet thoroughly tested in every detail.