Unify spelling of NotCongruent, update reference to file.
Merge pull request #2 from BenWiederhake/unify-spelling

Unify spelling of NotCongruent, update reference to file.
Made git ignore *.directory files in the images dir.
Fixed a typo in the description of \svg.
Some file renaming, for consistency.
Merge git://github.com/gfhcs/cp-material

Conflicts:
	images/iso_NotCongruent.dot
	images/iso_NotCongruent.pdf
	images/iso_NotCongruent.pdf_tex
	images/iso_NotCongruent.svg
	images/iso_incongruent.dot
	images/iso_incongruent.pdf
	images/iso_incongruent.pdf_tex
	images/iso_incongruent.svg
	images/iso_notCongruent.dot
	images/iso_notCongruent.pdf
	images/iso_notCongruent.pdf_tex
	images/iso_notCongruent.svg
	images/wBisim_NotCongruent.dot
	images/wBisim_incongruent.dot
	images/wBisim_notCongruent.dot
	äquivalenzen.tex