Enhancement: Convert Enum values to be compliant to .NET naming standards

[GoogleCodeExporter]

The naming guidelines for Google Protobuf enums is to use the C++/Java standard 
of all capitals:

enum MyEnum {
    OPTION_ONE =1;
    OPTION_TWO =2;
}

In .NET the naming standards are to use Pascal case (upper camel): 
http://msdn.microsoft.com/en-us/library/4x252001(VS.71).aspx

Please include a ProtoGen setting that will convert enumerated values to the 
.NET standard.  Expected output would be:

enum MyEnum {
    OptionOne,
    OptionTwo
}

Original issue reported on code.google.com by joew...@live.com on 4 Jan 2013 at 6:40