Instead of having to add and individually test the versions to check
for, we store the current version and test on that with a specific
function isAvailableAtLeastFrom(package, year, month, day)
Currently only used for the LaTeX version, but could also be extended
for package versions.
Of course this will only work if output_changes was true when creating the
.tex file.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@40139 a592a061-630c-0410-9148-cb99ea01b6c8
