improving docs: embedded pdfs and screenshots

The attached EPS-files have just been resaved with inkscape, reducing
their size.
(But how were they created? They look quite pixelated)

The attached PDFs from the docs-subdirectory have been recompressed.

They go from

186.560 bytes (197 KB on disk) for 8 items
114.493 bytes (127 KB on disk) for 8 items

These are just minimal gains.
But Zusammenfassung.pdf is unusually big and profits the most.


If docs looking the best they could is still a goal, then please have a
look at the terrible kerning in Zusammenfassung.pdf and Abstract.pdf
It looks like "A bsatz".


Further, the little screenshots used showcase mostly very outdated
font-diplay.
Please compare japanese macrobox.png with standard macrobox.png.
My guess is that almost no one anymore uses LyX on displays with such
bad font-display technology.
That means the lyx-docs look much worse on paper in what they are trying
to depict than what is actually on screen.

greetings
Mike