Added a new header file: SDL_loadso.h

It contains the following functions:
	SDL_LoadObject(), SDL_LoadFunction(), SDL_UnloadObject()
The UNIX esd and arts audio code use these to dynamically load
their respective audio libraries.

docs.html

@@ -16,6 +16,7 @@ be found at the <A HREF="http://www.libsdl.org/"> main SDL page</A>.
 Major changes since SDL 1.0.0:
 </H2>
 <UL>
+	<LI> 1.2.4: Added shared object loading functions in SDL_loadso.h
 	<LI> 1.2.4: Added SDL_LockRect() and SDL_UnlockRect()
 	<LI> 1.2.4: Incorporated XFree86 extension libraries into the source
 	<LI> 1.2.4: Added initial support for Atari (thanks Patrice!)