Fix DuplicateAnchorException when using merge keys do merge mappings …

…that contain aliases.

Implement merging a sequence of aliases.

Fix AnchorNotFoundException when another exception occurs during dese…

…rialization.

Update version number.

Separate IObjectDescriptor from IPropertyDescriptor to isolate access…

…ors from metadata.

Update changelog.

Release version 3.0.0.

Remove obsolete stuff.

Fix newline handling when emitting folded scalars.

Increment version number.

Fix TargetException when serializing a generic dictionary.