add newline feature to the text node, add about window with credits, add about menu with submenus

src/util.h

@@ -16,6 +16,7 @@ glm::vec4 rand_color();
 glm::vec3 convert_hsv2rgb(const glm::vec3 c);
 glm::vec3 convert_rgb2hsv(const glm::vec3 c);
 std::vector<std::string> split(const std::string& subject, char d, int max_split = 0);
+std::string unescape(const std::string& s);
 
 size_t curl_data_handler(void *contents, size_t size, size_t nmemb, void *userp);
 size_t curl_data_write(void *ptr, size_t size, size_t nmemb, FILE *stream);
@@ -26,7 +27,6 @@ inline glm::vec2 zw(const glm::vec4& v) { return glm::vec2(v.z, v.w); }
 inline glm::ivec2 xy(const glm::ivec4& v) { return glm::ivec2(v.x, v.y); }
 inline glm::ivec3 xyz(const glm::ivec4& v) { return glm::ivec3(v.x, v.y, v.z); }
 inline glm::ivec2 zw(const glm::ivec4& v) { return glm::ivec2(v.z, v.w); }
-
 inline glm::vec2 xy(const glm::vec3& v) { return glm::vec2(v.x, v.y); }
 
 template<typename T, int N> struct cbuffer