enhancing enums

[hehe45]

In c++ it is valid syntax to have trailing commas at the and of enum definitions:
enum {a, b, c, };
This would be a useful addition to D too.

The enum class syntax from c++0x should also adopted by D, this would allow named enums which are not automatically encased by a namespace:

enum EnumName {A, B, C};       ---> A, B and C are global constants
enum class EnumName {A, B, C};---> A, B and C are in the EnumName namespace