1. Rearrange SDRAM and SRAM layout. Move timing critical code to SRAM,
and the rest to SDRAM.
2. Add bootloader that's capable of FOTA over mbed cloud.
Signed-off-by: Tony Wu <tonywu@realtek.com>
If the file extra_targets.json exists in the working directory load it over the top of the built in targets.json for defining new and overriding built in mbed target definitions.
The input format is now determined by the OUTPUT_EXT key in
targets.json, and defaults to "bin" when not specified. This changes the
Teensy3_1 and the NRF51x targets' post bulid hooks.
Teensy3_1 just converted to intelhex, so we do nothing instead.
NRF51x assumed that it was taking in a bin format file. I made it detect
file type by extension.