Package installer service

Ass agreed with @sitereactor i have now made this pull request where everything is made internal for now
With this pull request it is possible to import packages from core api packaging service
I had to create a variant of PackageBinarynspector.cs (variant: PackageBinaryByteInspector.cs) since the installation now works directly from package instead of having a temporary directory. 
Maybe we should consider to compile the cs / vb files located in "App_Code" and use the output for the PackageBinarynspector?
I have merged the InstallAction and UninstallAction to one class since there are exactly the same.
Sure but arrays are still mutable which is the main concern, we'll most likely leave most of this stuff internal anyways so it's not a big deal but if you want to return an absolute pre-prepared collection you should use ReadOnlyCollection<T> or something similar or just stick to IEnumerable if it doesn't always specifically need to be a pre-prepared collection (which is quite rare)