Managing the API changelog in HTML has been rather burdensome, getting
the formatting correct and doing things like having numbered lists
added unneeded burden to the process.
This change moves all the old content to markdown and
places it prominently next to the other NewAndNoteworthy content.
Also included here is some fine tuning to the related documentation
about API.
Part of #32
This commit migrates all the N&N content from
https://wiki.eclipse.org/CDT/User/NewInCDT to GitHub.
For newer releases (>= CDT 10.0) the entire content has
been rewritten in GitHub flavour Markdown. For older
releases, the N&N page has simply been saved in a
rendered format.
