Deduplicate automation autoload path

Fixes #168
Fixes arch1t3cht#15

src/auto4_base.cpp

@@ -322,10 +322,14 @@ namespace Automation4 {
 
 		std::vector<std::future<std::unique_ptr<Script>>> script_futures;
 
+		std::set<std::filesystem::path> dirnames;
 		for (auto tok : agi::Split(path, '|')) {
 			auto dirname = config::path->Decode(std::string(tok));
 			if (!agi::fs::DirectoryExists(dirname)) continue;
 
+			if (dirnames.count(dirname)) continue;
+			dirnames.insert(dirname);
+
 			for (auto filename : agi::fs::DirectoryIterator(dirname, "*.*"))
 				script_futures.emplace_back(std::async(std::launch::async, [=] {
 					return ScriptFactory::CreateFromFile(dirname/filename, false, false);