Extend Classes Syntax for anonymous / inner / outer classes

[codecholeric]

It would be neat to have classes().that().

• areAnonymous()
• areInnerClasses() (includes anonymous classes, do we need areNamedInnerClasses()?)
• areOuterClasses() (i.e. no enclosing class / toplevel, I'm open for better naming 😉)

Same holds for classes().should().be...

[codecholeric]

Overlaps in parts with #172

[rweisleder]

The JLS defines four different kinds of classes, see chapter 8.

With this reference I suggest to add the methods classes().that().

• areTopLevelClasses()
• areNestedClasses()
• areLocalClasses()
• areAnonymousClasses()

And of course the same for classes().should().be...

To be consistent with existing methods we should also add the negated methods like areNotTopLevelClasses() and notBeTopLevelClasses().

[codecholeric]

We should also make the determination of the nested class type more resilient. Currently isAnonymous() is implemented by checking the simple name for being empty. The class file import should be able though, to derive a type of the nested class (static nested, inner, local, anonymous) and pass that on to the JavaClass instead of applying some heuristics later (since for a local class this would be something shady like javaClass.getName().matches(".*\\$\\d+\\w+") or similar 😨)

[rweisleder]

I started working on this issue.