Multiple local classes can share the same name

[Jesper Öqvist]

JastAddJ accepts multiple local classes with the same name. This should not be allowed.

Example:

void m() {
    class A {};
    class A {};
}

[Jesper Öqvist]

Added name checking for local class decls

fixes issue #25 (bitbucket)

→ <<cset ab5921bdaf5b>>