Improve indentation for doc comments

Doc comments are now split at their source, as a first step in
normalizing their indentation between VS and MD.
Generate bindings for testing (WIP)
Generate bindings for testing (WIP2)
Corrected indentation
Corrected declarations in convenience overloads
Plural name to singular in convenience overloads
Return types must be cls-compliant

CreateCLSCompliantWrappers must always change return types into
cls-compliant types. The reason is that we cannot overload on return
type alone, so we should always choose the compliant version.
Move convenience overloads to generator

The generator now handles the creation of convenience overloads. These
must be removed from the helper classes to avoid redefinition errors.