Plugin loading is now multithreaded.

Performance improvement is limited when Skyrim.esm is hundreds or
thousands of times larger than most other plugins though. Will have to
speed up the actual reading code to do significantly better, I think.

src/gui/main.cpp

@@ -53,11 +53,14 @@
 #include <boost/log/utility/setup/file.hpp>
 #include <boost/log/utility/setup/common_attributes.hpp>
 #include <boost/log/support/date_time.hpp>
+#include <boost/thread/thread.hpp>
 
 #include <wx/snglinst.h>
 #include <wx/aboutdlg.h>
 #include <wx/progdlg.h>
 
+#define BOOST_THREAD_VERSION 4
+
 IMPLEMENT_APP(BossGUI);
 
 using namespace boss;
@@ -67,6 +70,20 @@ using boost::format;
 namespace fs = boost::filesystem;
 namespace loc = boost::locale;
 
+
+struct plugin_loader {
+    plugin_loader(boss::Plugin& plugin, boss::Game& game, const string& filename, bool b) : _plugin(plugin), _game(game), _filename(filename), _b(b) {}
+    
+    void operator () () {
+        _plugin = boss::Plugin(_game, _filename, _b);
+    }
+
+    boss::Plugin& _plugin;
+    boss::Game& _game;
+    string _filename;
+    bool _b;
+};
+
 bool BossGUI::OnInit() {
     
     //Check if GUI is already running.
@@ -394,17 +411,22 @@ void Launcher::OnSortPlugins(wxCommandEvent& event) {
     
     // Get a list of the plugins.
     list<boss::Plugin> plugins;
+    boost::thread_group group;
     for (fs::directory_iterator it(_game.DataPath()); it != fs::directory_iterator(); ++it) {
         if (fs::is_regular_file(it->status()) && IsPlugin(it->path().string())) {
 
             string filename = it->path().filename().string();
 			BOOST_LOG_TRIVIAL(trace) << "Reading plugin: " << filename;
-			boss::Plugin plugin(_game, filename, false);
-            plugins.push_back(plugin);
+
+            plugins.push_back(boss::Plugin());
+            
+            plugin_loader pl(plugins.back(), _game, filename, false);
+            group.create_thread(pl);
 
             progDia->Pulse();
         }
     }
+    group.join_all();
 
     if (fs::exists(_game.MasterlistPath())) {
         BOOST_LOG_TRIVIAL(trace) << "Parsing masterlist...";