CTFE Status

[Stefan Koch via Digitalmars-d]

Function pointers and other advanced features interfere with the 
ability to cache bytecode I just never noticed because the 
bytecode caching feature was disabled a long time.
Since I do not know how much of it is bitrot I removed it 
alltogether.
This feature will return and be more performant, when the outside 
function-arguments are getting fixed.
When this is done we can also remove a few special cases for the 
interpreter backend which is always good.