Merge commit '0f0b9b1'

Merge commit '146ab0e'

Merge commit '1979fc4'

Merge commit '1052a67'

• Moved Otago plain theme from the subtree where it was inadvertently placed to the actual Beamer themes repository.

• Created new “plain” Otago beamer theme without all the fussy coloured headers and footers.

Merge commit '0c1f2e1'

Merge commit '75f193f' as 'beamerthemes'