mbed library sources, mbed-dev only for TYBLE16

Fork of mbed-dev by mbed official

Please refer flowing link.
/users/kenjiArai/notebook/tyble16-module-will-become-a-mbed-family--mbedliza/

Revision:
169:e3b6fe271b81
Parent:
167:e84263d55307
--- a/targets/TARGET_NORDIC/mbed_rtx.h	Thu Jul 06 15:42:05 2017 +0100
+++ b/targets/TARGET_NORDIC/mbed_rtx.h	Wed Jul 19 17:31:21 2017 +0100
@@ -37,6 +37,8 @@
 #define INITIAL_SP              (0x20010000UL)
 #endif
 
+#define OS_IDLE_THREAD_STACK_SIZE  512
+
 #elif defined(TARGET_MCU_NRF52840)
 
 #ifndef INITIAL_SP