Fix TClassAttributeMap and TClass
Fixes to RemoveProperty
Now if `TGraph::Draw()` is invoked without parameter and if there is no axis defined in the current canvas, the option `ALP` is automatically set.
Small changes to synchronize with the patches branch
Add missing initialization
Added (failing) tests for TChain
Passing a few of the first tests with a TChain

All but one line contributed by Axel Naumann
Added function to get fEnv variable to check for validity
Working reading of most TChain tests (undeterministic behaviour)
Fix for undeterministic behaviour caused by tree pointer

Contributed by Axel Naumann
Code cleanup in tests
Removed unnecessary Error messages and calls to Setup
Added comment for getter
Avoid reading file on initialize