Restructure source and resource files (#46)

importantly, res is now res/res and css is now res/css

src/state.cpp

@@ -0,0 +1,37 @@
+#include "state.hpp"
+
+void to_json(nlohmann::json &j, const ExpansionStateRoot &m) {
+    if (m.Children.empty()) {
+        j = nlohmann::json::object();
+    } else {
+        for (const auto &[id, state] : m.Children)
+            j[std::to_string(id)] = state;
+    }
+}
+
+void from_json(const nlohmann::json &j, ExpansionStateRoot &m) {
+    for (const auto &[key, value] : j.items())
+        m.Children[key] = value;
+}
+
+void to_json(nlohmann::json &j, const ExpansionState &m) {
+    j["e"] = m.IsExpanded;
+    j["c"] = m.Children;
+}
+
+void from_json(const nlohmann::json &j, ExpansionState &m) {
+    j.at("e").get_to(m.IsExpanded);
+    j.at("c").get_to(m.Children);
+}
+
+void to_json(nlohmann::json &j, const AbaddonApplicationState &m) {
+    j["active_channel"] = m.ActiveChannel;
+    j["expansion"] = m.Expansion;
+}
+
+void from_json(const nlohmann::json &j, AbaddonApplicationState &m) {
+    if (j.contains("active_channel"))
+        j.at("active_channel").get_to(m.ActiveChannel);
+    if (j.contains("expansion"))
+        j.at("expansion").get_to(m.Expansion);
+}