[isabelle-dev] NEWS (update)

[Makarius]

* Simplified main Isabelle executables, with less surprises on
case-insensitive file-systems (such as Mac OS).

  - The main Isabelle tool wrapper is now called "isabelle" instead of
    "isatool."

  - The former "isabelle" alias for "isabelle-process" has been
    removed (should rarely occur to regular users).

  - The former "isabelle-interface" and its alias "Isabelle" have been
    removed (interfaces are now regular Isabelle tools).

Within scripts and make files, the Isabelle environment variables
ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
respectively.  (The latter are still available as legacy feature.)

The old isabelle-interface wrapper could react in confusing ways if
the interface was uninstalled or changed otherwise.  Individual
interface tool configuration is now more explicit, see also the
Isabelle system manual.  In particular, Proof General is now available
via "isabelle emacs".

INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
purge installed copies of Isabelle executables and re-run "isabelle
install -p ...", or use symlinks.