Improve beamer collorary argument conversion (#8828)
Unify string (part of #8826)
Fix installation of springer examples
Merge branch 'master' of git://git.lyx.org/lyx into my-two-cents

# By Juergen Spitzmueller
# Via Juergen Spitzmueller
* 'master' of git://git.lyx.org/lyx:
  Fix installation of springer examples
  Unify string (part of #8826)
  Improve beamer collorary argument conversion (#8828)