* Also enhanced reporting error exit reporting through the scons logger to provide
the exception in the compilation report.
* More error exits in scons should do this.
* We were using "None" here, which causes at least with Python3.6
and higher incompatible behaviour.
* Added test that demonstrates ability to import from itself with
those newer versions.
* Very useless feature, but bug compatible we are with this.
* Only at load time, the value is decided, so do not statically optimize
for "__package__" as it is subject to change in those cases.
* Also, do not assign module attributes in the node tree, merely have
special references for them, generated in case of no other assignment
being seen. This affects "__loader__" and "__spec__" mostly
* The new nodes were moved to a new nodes module, along with the node
that handles "__file__" already.
