add a helper library, uart_repl, which handles basic ANSI over UART

examples/uart_repl_test/uart_repl_test.c

@@ -0,0 +1,31 @@
+#include <stdlib.h>
+#include <string.h> /* strlen */
+
+#include <espressif/esp_common.h>
+#include <espressif/user_interface.h>
+#include <esp/uart.h>
+#include <FreeRTOS.h>
+#include <task.h>
+
+#include <uart_repl/uart_repl.h>
+
+
+void handle_command(char const d[]) {
+	if (!strcmp(d, "ts") || !strcmp(d, "time")) {
+		printf("the tick count since boot is: %u\n", xTaskGetTickCount());
+	} else if (!strcmp(d, "help")) {
+		printf("commands include ts, time\n");
+	} else {
+		printf("command not recognized, try help\n");
+	}
+}
+
+
+void user_init(void) {
+	uart_set_baud(0, 115200);
+
+	printf("\n\nWelcome to the uart REPL demo. try \"help\"\n");
+	uart_repl_init(&handle_command);
+}
+
+