Added latest changes from F# sample pack
enable default value for generated types
http://fsharp3sample.codeplex.com/SourceControl/changeset/25487

Use custom 'HasDefaultParameterValue' property instead of overridding
http://fsharp3sample.codeplex.com/SourceControl/changeset/25529
Updated ProvidedTypes.fs to support mono for casting of generic reference types
Merge pull request #631 from 7sharp9/master

Added latest changes from F# sample pack