Implement IRoInterface (#445)

* Implement IRoInterface

This is required by Super Mario Party.
This commit also adds MapProcessCodeMemory and UnmapProcessCodeMemory functions in KMemoryManager. Those two calls might not reflect what the SVC of the same names do.

* Fix some code style issues

* Use MakeError to clarify error code

* Add NRR and NRO constants

* Fix some codestyle issues

* Fix InvalidMemoryState error code

Ryujinx.HLE/Loaders/Executables/IExecutable.cs

@@ -8,6 +8,9 @@ namespace Ryujinx.HLE.Loaders.Executables
         byte[] RO   { get; }
         byte[] Data { get; }
 
+        long SourceAddress { get; }
+        long BssAddress    { get; }
+
         int Mod0Offset { get; }
         int TextOffset { get; }
         int ROOffset   { get; }