UFCS overloads
Foreach over arrays and slice, and no ref.
forach range, still no ref parameters
indetifier[identifier] resolve to index expression or array types (no aa for now)
foreach ref parameters
Remove special casing of pointer for increment/decrement as it is now handled by the backend
Remove multiple argument for IndexExpression in the IR as it do not make sense anyway.
Imporve evaluator API
Simplify getLvalue
Make type qualifier transitives
Implement __traits() parsing
added abstract class Aggregate