Added SDRAM support for stm32f429-stm32f4discovery

miosix/_doc/textdoc/Changelog.txt

miosix/_tools/ram_test/main.cpp

...tm32f4/stm32f429zi_stm32f4discovery/core/stage_1_boot.cpp

...32f4/stm32f429zi_stm32f4discovery/interfaces-impl/bsp.cpp

...4/stm32f429zi_stm32f4discovery/interfaces-impl/bsp_impl.h

..._stm32f4/stm32f429zi_stm32f4discovery/stm32_2m+6m_xram.ld

..._stm32f4/stm32f429zi_stm32f4discovery/stm32_2m+8m_xram.ld

miosix/config/Makefile.inc

miosix/config/miosix_settings.h

miosix_np_2/nbproject/configurations.xml