CMake: modernize in view of vcpkg

Unit tests now under CTest control, and some little work on CMake and Windows dependences

Wuttke, Joachim authored 4 years ago and Wuttke, Joachim committed 4 years ago

Bug came from my misunderstanding CMake syntax

not just for debugging, keep it in the long run:
onlys so we get info about what DLLs are packed
into the executable

option -v (verbose) is not helpful

Wuttke, Joachim authored 4 years ago and Wuttke, Joachim committed 4 years ago

Our patch, https://gitlab.kitware.com/cmake/cmake/-/merge_requests/4934,
is expected to be released with CMake 3.19. Therefore we shall removed
FindTIFF.cmake from the BornAgain sources, once our minimum required
CMake version has been incremented accordingly.

Compilation no longer enforces unit test runs

Core: simplify computation of bottom and top; provide test coverage; rm shape classes

Unit tests: Remove unnecessary destructors

Updated doxygen comments

Added Doxygen class comments. Renamed WallclockTimer <- TimeInterval

Provide doxygen comments.
Use seconds from the onset.
Internal data now struct, not class.

Discover that the promise of 1% accuracy is not kept.
TODO: Replace vertex-based approximation for bottomZ and topZ
of cylinder, cone, ellipsoid etc

From this we learn that the rotation axis is at the bottom,
not at the center of the particle.

Remove explicit code for destructors, and some constructors,
that are automatically defined by modern C++.
Also unpointerize a few objects.