Doxygen comments.

Outcomment Python compilation.
Work on layout while studying code.

Insert new header comment block, remove old one, manually improve file comments (defines / implements), change brief function description to doxygen format, remove some outcommented code

Fixed bug in InterferenceFunction2DParaCrystal; fixed warnings about size_t -> int conversions; updated Xcode project file

Added parameter registration, xi integration flag usage, isgisaxs8 first sample initialization, debug symbols in release