Portage of Oberon system to stm32f429i-disco board

Version 13 released!

Oberon System

A rudimentary image manipulation module has been added. It allows to display 8bpp indexed colors BMP and can take screenshots.

The 12th release contains a major improvement. The modules code and strings can be hosted in the flash memory of the microcontroller and be executed in place. The global data can also be placed is SRAM.  Previously, the modules had too be loaded in the SDRAM to be executed.  

There are a lot of advantages doing this:  

• The code executes 8 times faster, by avoiding the competition between CPU and VGA system for SDRAM access.  
• More SDRAM is available for modules that remains in SDRAM and for the heap.
• If the Oberon system and the compiler are both placed in embedded flash memory, the system is guaranteed to boot and compile even if incoherent recompilation has been done on vital modules.