Updated README. Added example config. Added default font for ease of use.

sdl_helpers.h

@@ -8,6 +8,8 @@
 
 #include "json.hpp"
 
+std::string default_font_name = "font.ttf";
+
 // Call this before everything
 // Prints its messages
 bool init_sdl();
@@ -17,7 +19,7 @@ void clean_sdl();
 
 // A simple way to get a font pointer to use
 // Can return NULL
-TTF_Font* get_font(const std::string& filename, int size);
+TTF_Font* get_font(int size, const std::string& filename = default_font_name);
 
 // Reads the file and tries to parse a JSON file with comments
 // cfg - output json struct