Make :exists and :delete up to spec

The :exists and :delete adverbial pairs on hash accesses were always
interpreted as "true".  Which makes constructs as :!exists or :delete($really)
not work.
add link, symlink, and chmod to RESTRICTED.setting
Volunteer for #66
[spectest.data] mark t/spec/S32-str/substr.t as # icu
Merge remote-tracking branch 'upstream/nom' into nom
[src/core] add .Set and .Bag to List and Parcel
Merge pull request #149 from lizmat/adverbialexistsdelete

Make :exists and :delete up to spec
Allow slice with :exists adverb on hashes

For some reason a "die" was here, whereas the spec says it should return a
Parcel of Bool.
Merge remote-tracking branch 'upstream/nom' into nom

Conflicts:
	src/core/Any.pm
Merge remote-tracking branch 'upstream/nom' into nom

Conflicts:
	src/core/Any.pm