Add -lastproject editor command-line option to open the last project

Source/Editor/Editor.cpp

@@ -537,6 +537,13 @@ int32 Editor::LoadProduct()
     if (FileSystem::FileExists(lastProjectSettingPath))
         File::ReadAllText(lastProjectSettingPath, lastProjectPath);
 
+    // Try to open the last project when requested
+    if (projectPath.IsEmpty() && CommandLine::Options.LastProject.IsTrue())
+    {
+        if (!lastProjectPath.IsEmpty() && FileSystem::DirectoryExists(lastProjectPath))
+            projectPath = lastProjectPath;
+    }
+
     // Missing project case
     if (projectPath.IsEmpty())
     {

Source/Engine/Engine/CommandLine.cpp

@@ -155,6 +155,7 @@ bool CommandLine::Parse(const Char* cmdLine)
     PARSE_BOOL_SWITCH("-clearcache ", ClearCache);
     PARSE_BOOL_SWITCH("-clearcooker ", ClearCookerCache);
     PARSE_ARG_SWITCH("-project ", Project);
+    PARSE_BOOL_SWITCH("-lastproject ", LastProject);
     PARSE_BOOL_SWITCH("-new ", NewProject);
     PARSE_BOOL_SWITCH("-genprojectfiles ", GenProjectFiles);
     PARSE_ARG_SWITCH("-build ", Build);

Source/Engine/Engine/CommandLine.h

@@ -147,6 +147,11 @@ public:
         /// </summary>
         String Project;
 
+        /// <summary>
+        /// -lastproject (Opens the last project)
+        /// </summary>
+        Nullable<bool> LastProject;
+
         /// <summary>
         /// -new (generates the project files inside the specified project folder or uses current workspace folder)
         /// </summary>