QAIC, QAIcc, AICc rewritten to use common function .aic
QAIC[c] gains new argument REML
minor corrections to the manual

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/mumin@314 edb9625f-4e0d-4859-8d74-9fd3b1da38cb