Code in #if !__MonoCS__ is grayed out

[dgrunwald]

The Mono compiler always defines the built-in symbol __MonoCS__.
The directive #if !__MonoCS__ is used to disable a section of code under the Mono compiler.
SharpDevelop 5.0 displays such sections in a grayed out color as if they were inactive (because NRefactory internally uses the Mono C# parser). However, this is incorrect because we use the Microsoft compilers when building, so the section is active.