Adding processor flash memory reading, viewing and writing to file.

Works when the device is running either osimage or bootloader.

- New memory reading command in osimage and bootloader.
- Extended 'hw readmem' command with length parameter, file writing and hex viewer.
- Introduced '--dumpmem' option to proxmark3 executable to support dumping from bootloader.

Simple interactive examples:
  hw readmem -f flashdump
  hw readmem -l 1024
CLI example:
  ./pm3 --dumpmem flashdump.bin

Reading from arbitrary memory ranges can be unlocked using the 'raw' option.

armsrc/util.h

@@ -103,4 +103,7 @@ int BUTTON_HELD(int ms);
 bool data_available(void);
 bool data_available_fast(void);
 
+uint32_t flash_size_from_cidr(uint32_t cidr);
+uint32_t get_flash_size(void);
+
 #endif