Support constants on class-string<Foo>

[spaze]

• Support $foo::BAR where $foo is declared as class-string<Foo>, this partly fixes a very old issue (Support $foo::BAR where $foo is declared as class-string<Foo> #186, thanks @eithed)

Internal change:

• Leading namespace separator is now removed consistently in one place (\Name\Space → Name\Space) (Remove the initial namespace separator from class names in one place #187)

---

This discussion was created from the release Support constants on class-string.

[spaze]

2.14.0 has introduced a regression bug so I've replaced it with 2.14.1 which fixes the issue #189.