Documentation: Doxygen page about interference functions (text and figures), UserManual (modifications of ff.tex and interferences.tex)

Parallelepiped form factor removed.
Corrections of some bugs in FormFactor InfiniteLongBox

Pdf versions of contour plots for output intensity for all form factors in User Manual Appendix.
Addition of a description of Core Shell particle in User Manual Appendix.

Form factors: addition of appendix to User Manual, schematic views and missing information to Doxygen

New doxygen docs switched on, Doxyfile.in is introduced for automatic propagation of version number in the project.

- no latex output
- html output goes to BornAgain/html

MesoCrystal test is off, new fitting examples for spheres in a lattice and corresponding changes in visitors

On the way to add roughnesses of layers: new classes IRoughness, LayerInterface, lots of comments and const references. New Doc/Doxyfile for oxygen generation.