added failFast option

fixes gh-1

spring-cloud-config-sample/src/test/java/sample/ApplicationFailFastTests.java

@@ -0,0 +1,24 @@
+package sample;
+
+import org.junit.Test;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+
+import static org.junit.Assert.*;
+
+public class ApplicationFailFastTests {
+
+	@Test
+	public void contextLoads() {
+        try {
+            new SpringApplicationBuilder()
+                    .sources(Application.class)
+                    .run("--server.port=0",
+                            "--spring.cloud.config.failFast=true",
+                            "--spring.cloud.config.uit=http://server-host-doesnt-exist:1234");
+            fail("failFast option did not produce an exception");
+        } catch (Exception e) {
+            assertTrue("Exception not caused by fail fast", e.getMessage().contains("fail fast"));
+        }
+    }
+
+}