SDL renderer improvements and fixes and added SDL OpenGL option;

Various performance improvements;
Fixed USB UHCI HCHalt;
Cirrus Logic CL-GD 5422/24 fixes and removed them from the Dev branch;
The Storage controllers sections of Settings now has its own corresponding section of the configuration file;
Fixed the AT clock divisors for some Pentium OverDrive CPU's;
Added the ACPI RTC status (no ACPI RTC alarm event yet).

src/include/86box/86box.h

@@ -177,6 +177,7 @@ extern uint16_t	get_last_addr(void);
    should be in cpu.c but I put it here to avoid
    having to include cpu.c everywhere. */
 extern void	sub_cycles(int c);
+extern void	resub_cycles(int old_cycles);
 
 extern double	isa_timing;
 extern int	io_delay;