support for ext4/EMMC filesystems in updater binary

Make the mount and format functions take extra parameters describing
the filesystem type and add support for mounting and formatting ext4
filesystems on EMMC.

Change recovery to consistently use stdout for status messages instead
of mixing stdout and stderr.
diff --git a/common.h b/common.h
index a428dab..333417f 100644
--- a/common.h
+++ b/common.h
@@ -72,12 +72,12 @@
 void ui_reset_progress();
 
 #define LOGE(...) ui_print("E:" __VA_ARGS__)
-#define LOGW(...) fprintf(stderr, "W:" __VA_ARGS__)
-#define LOGI(...) fprintf(stderr, "I:" __VA_ARGS__)
+#define LOGW(...) fprintf(stdout, "W:" __VA_ARGS__)
+#define LOGI(...) fprintf(stdout, "I:" __VA_ARGS__)
 
 #if 0
-#define LOGV(...) fprintf(stderr, "V:" __VA_ARGS__)
-#define LOGD(...) fprintf(stderr, "D:" __VA_ARGS__)
+#define LOGV(...) fprintf(stdout, "V:" __VA_ARGS__)
+#define LOGD(...) fprintf(stdout, "D:" __VA_ARGS__)
 #else
 #define LOGV(...) do {} while (0)
 #define LOGD(...) do {} while (0)