An old example file is actually a classification problem of quadrilaterals. Tags are changed accordingly.
Missing tags added.
Missing chapter tags added.
Merge branch 'master' of git://github.com/openwebwork/webwork-open-problem-library
Merge branch 'master' of git://github.com/openwebwork/webwork-open-problem-library
Merge branch 'master' of git://github.com/openwebwork/webwork-open-problem-library
Merge branch 'master' of git://github.com/openwebwork/webwork-open-problem-library
New graph theor application problem.
New graph theory application problems.