build: W600-SDK importiert, Firmware-Build und Hello am EVK

Docker-Build mit gcc-arm-none-eabi 4.9-2014q4 (statt Homebrew-Cask) verwendet,
Dockerfile/tools/docker.sh dafür aus Task 13 vorgezogen. cmake/sdk.cmake schont
gcc 4.9 (kennt -fcommon/-Wno-error=... nicht). Zwei zusätzliche SDK-Stubs
(EarlyInit, pre_gpio_config) in src/sys/sdk_stubs.c ergänzt, siehe sdk/PATCHES.md.

src/app_main.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+
+#include "wm_include.h"
+
+#define NL_APP_TASK_PRIO 40
+static u32 s_app_stack[512];
+
+static void app_task(void *arg)
+{
+    unsigned int n = 0;
+    (void)arg;
+    for (;;) {
+        printf("ninlight %s alive %u\r\n", NINLIGHT_DEVICE_ID, n++);
+        tls_os_time_delay(HZ);
+    }
+}
+
+void UserMain(void)
+{
+    printf("\r\nninlight %s for %s (built %s)\r\n", NINLIGHT_FW_VERSION, NINLIGHT_DEVICE_ID, NINLIGHT_BUILD_DATE);
+    tls_os_task_create(NULL, "nl_app", app_task, NULL, (u8 *)s_app_stack, sizeof(s_app_stack), NL_APP_TASK_PRIO, 0);
+}