Log Message:
Update to Squeak 4.0

Squeak 4.0 is functionally equivalent to the previous Squeak 3.10.2 release
but licensed under the MIT license original parts remaining under the Apache
license.

Current development work will be released as 4.1 as soon as possible
following the release of 4.0.

pkgsrc changes:
- move machine-independent files into "share" hierarchy;
- set licence;
- fix homepage.