support ft_232h, cp210_ multiport devices

harmonize claimInterface() error handling
cancel read() on close()

usbSerialExamples/build.gradle

@@ -1,12 +1,12 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 26
+    compileSdkVersion 27
     buildToolsVersion '27.0.3'
 
     defaultConfig {
         minSdkVersion 14
-        targetSdkVersion 26
+        targetSdkVersion 27
 
         testInstrumentationRunner "android.test.InstrumentationTestRunner"
     }