Improved latex formatting

[janscience]

So, here come some final fixes:

• improved formatting of first and middle Names.
  There were problems with names given as 'H.J.' or 'MS', as well as with 'Hans-Juergen'.
  Run

python3 -m gca.core

to see this at work. Ideally you move this test code in `main` to some test script...

- Abstract titles in the latex file get a final full stop stripped

- Added latex command for including a figure.