Complete refactor of project file structure

Fix incorrect handing of default node parameters in SSD subscription.
Fix unable to parse some Clash rule-providers (#289).
Fix not filtering inline comments in some Surge rulesets. (#285)
Add Cron task options.
Add clean context option for persisting a JS context across the whole request.
Replace JS engine with QuickJS.

src/utils/yamlcpp_extra.h

@@ -0,0 +1,44 @@
+#ifndef YAMLCPP_EXTRA_H_INCLUDED
+#define YAMLCPP_EXTRA_H_INCLUDED
+
+#include <yaml-cpp/yaml.h>
+#include <string>
+#include <vector>
+
+template <typename T> void operator >> (const YAML::Node& node, T& i)
+{
+    if(node.IsDefined() && !node.IsNull()) //fail-safe
+        i = node.as<T>();
+};
+
+template <typename T> T safe_as (const YAML::Node& node)
+{
+    if(node.IsDefined() && !node.IsNull())
+        return node.as<T>();
+    return T();
+};
+
+template <typename T> void operator >>= (const YAML::Node& node, T& i)
+{
+    i = safe_as<T>(node);
+};
+
+using string_array = std::vector<std::string>;
+
+inline std::string dump_to_pairs (const YAML::Node &node, const string_array &exclude = string_array())
+{
+    std::string result;
+    for(auto iter = node.begin(); iter != node.end(); iter++)
+    {
+        if(iter->second.Type() != YAML::NodeType::Scalar)
+            continue;
+        std::string key = iter->first.as<std::string>();
+        if(std::find(exclude.cbegin(), exclude.cend(), key) != exclude.cend())
+            continue;
+        std::string value = iter->second.as<std::string>();
+        result += key + "=" + value + ",";
+    }
+    return result.erase(result.size() - 1);
+}
+
+#endif // YAMLCPP_EXTRA_H_INCLUDED