accept @pure @nothrow @return attributes

[Dicebot via Digitalmars-d]

It was sad that calls for more breakage were mostly ignored. But 
there is one thing now that is even worse - referring to 
#pleasebreakmycode as an excuse to introduce random changes based 
on random reddit comment - and completely dismissing everything 
that was said on topic initially. Resulting in exactly the 
opposite action that was asked to.

Please, revert this PR asap. After that it can possibly be 
introduced after meeting necessary prerequisites:

1) explanation of problem it fixes
2) design rationale for new model
3) evaluation of ROI
4) tools for simple migration - either as part of dfix or compiler

This is absolutely mandatory list for any change of language 
fundamentals to be considered legitimate.