Changeset 2688 for trunk/sources/HeuristicLab.PluginInfrastructure/Manager/PluginFile.cs

Implemented an enumerable to iterate through all PluginFiles as suggested by swagner, replaced the Assemblies enumerable with an AssemblyName enumerable for internal usage in the plugin infrastructure and replaced Assembly.LoadFrom calls with Assembly.Load() to prevent loading from GAC as far as possible.

#850 (PluginInfrastructure should provide a way to get assemblies associated with a plug-in)