Fonts in OpenGL

The fonts are made by next algorithm:

- enable font operations via SDL_ttf (GLFontRenderer)

- when appears a text, with a specified font, on demand it will be reused if doesn't exist already (GLFontRenderer based on a GLFontManager creates a GLFont)

- secondly it creates a for specified font, the color and style if is not already set (GLFont does the setup which creates a GLFontTextureList)

- for letters that are used, it will creates image pictures and it will create a texture for them (GLFontTextureList::TextOut) and meshcontainers for them