add 'camera' library

src/logic/scripting/lua/libcamera.cpp

@@ -0,0 +1,18 @@
+#include "api_lua.hpp"
+
+#include "../../../content/Content.hpp"
+#include "../../../world/Level.hpp"
+
+using namespace scripting;
+
+int l_index(lua::State* L) {
+    auto name = lua::require_string(L, 1);
+    auto& indices = content->getIndices(ResourceType::CAMERA);
+    std::cout << "index: " << name << std::endl;
+    return lua::pushinteger(L, indices.indexOf(name));
+}
+
+const luaL_Reg cameralib [] = {
+    {"index", lua::wrap<l_index>},
+    {NULL, NULL}
+};