Description of ARM_security_properties example for the release notes
Mention space-wastage bug in Overload in release notes.
Fix bug in emacs mode's handling of open thyname.

Problem arose if the thyname included the string "_fun_".
Thanks to Magnus for the bug report.

You will need to do a fresh ML < tools/smart-configure.sml
to get the new version of the Emacs mode created.
Travis: try to capture some more examples in our automatic builds
Improve some wording about using/building (Poly/ML) heaps.
Make Travis build core system in -expk as well as -stdknl.

Also shortened the "built with Poly in /usr/bin" test-case. If this
can get as far as building bossLib, then there's no reason to imagine
it failing later on. And why stress the free service at Travis unduly?
Merged with master