Consistency of usage of the word LaTeX in the documentation

The word LaTeX was used as just the word and on other places as \f$\mbox{\LaTeX}\f$
This has been made more consistent by means of the definition of the Alia \LaTeX (similar for \TeX)
Some names of executables etc. were not set in a 'code' font.

This fix replaces the fix from feature/bug_docu_latex pull request 149