Added a property Resources to IAssembly and IUnresolvedAssembly.

This property contains all embedded (/resource csc command line option) and linked (/linkresource option) resources. There is also something known as an "asssembly-linked" resource, but this is not supported because my Google-fu has failed me in finding out what it actually is and how to create one.

As discussed in #133, no resource data is being kept in memory unless the ```GetResourceStream``` method is used.