Enhance object members integration tests

* Isolate tests.
* Add tests for non-inheritable and inheritable-only members.
* Add systematic tests of members called with explicit self.
Add integration tests of setter members

i.e. bound members that, when called, change other members of $self.
Add unit tests for withBoundSelf function
Implement withBoundSelf function
Use withBoundSelf in bindMember
Merge pull request #5 from jkuczm/fix_bound_self

Fix setting members of $self inside bound member