Merge commit '1521b07' as 'ouexam'

Squashed 'ouexam/' content from commit 4af57f4 ...

git-subtree-dir: ouexam
git-subtree-split: 4af57f4

• Removed ouexam submodule.

Merge commit '75f193f' as 'beamerthemes'

Squashed 'beamerthemes/' content from commit eb14121 ...

git-subtree-dir: beamerthemes
git-subtree-split: eb14121

• Removed beamerthemes submodule.

Merge commit '7e71120' as 'listings'

Squashed 'listings/' content from commit 2b503ad ...

git-subtree-dir: listings
git-subtree-split: 2b503ad

• Removed listings submodule.

Merge commit '01b673a' as 'lectures'

Squashed 'lectures/' content from commit 2b1085b ...

git-subtree-dir: lectures
git-subtree-split: 2b1085b

• Removed lectures submodule.

• [lectures] Added amsmath.

• [ouexam] Updated FAQs.

• [ouexam] Corrected pdfpagemode parameter value.

• [ouexam] Corrected 2.4 release date.

• [ouexam] Added missing 2.4 release notes.

• [ouexam] Added new calculator instructions and merged 2.4 dev into master branch.

• [ouexam] Fixed non-functional running totals and added embargo class option.

• [ouexam] Updated documentation for 2.4 release.

• [lectures] Fixed incorrect Roman font in math mode.

• [ouexam] Merged Makefile fixes from master into dev.

• [ouexam] Fixed ancient misnamed make variable in installation instructions.

• [ouexam] Switched to pgfkeys instead of kvoptions.

• [ouexam] Initial not-working attempt to implement key-value options for environments.

• [ouexam] Added examsection* environment and better support for zero-mark questions.

• [lectures] Added \tinyskip macro.

• [lectures] Added document class for assignments.

• [lectures] Changed height of sans and mono fonts for XeLaTeX.

• [lectures] Tidied up XeLaTeX font handling and added font fix for digits in hyperlinks.