Allow plugin to have dependencies

[shargon]

Needed for https://github.com/neo-project/neo-modules/pull/160/files#diff-69f5bb07d501e021b374318421e22b7cR17

Related to neo-project/neo-node#508

[erikzhang]

You don't need to load the dependencies. It will load them automatically if you put them in the right place.

[erikzhang]

neo/src/neo/Plugins/Plugin.cs

Line 43 in 0f75741

AppDomain.CurrentDomain.AssemblyResolve += CurrentDomain_AssemblyResolve;

neo/src/neo/Plugins/Plugin.cs

Lines 83 to 104 in 0f75741

	private static Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
	{
	if (args.Name.Contains(".resources"))
	return null;
	Assembly assembly = AppDomain.CurrentDomain.GetAssemblies().FirstOrDefault(a => a.FullName == args.Name);
	if (assembly != null)
	return assembly;
	AssemblyName an = new AssemblyName(args.Name);
	string filename = an.Name + ".dll";
	try
	{
	return Assembly.Load(File.ReadAllBytes(filename));
	}
	catch (Exception ex)
	{
	Utility.Log(nameof(Plugin), LogLevel.Error, $"Failed to resolve assembly or its dependency: {ex.Message}");
	return null;
	}
	}

[shargon]

But then we need to to copy the dependencies outside the Plugin folder

[erikzhang]

@shargon Please review #1349