Various minor changes on optee examples

Prefix test applications for the examples with 'optee_example_'.
Gitignore the generate test applications.
Few extra minor changes as make verbosity and source coding style.
STR_TRACE_USER_TA is deprecated.
Update README.

Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
diff --git a/random/Android.mk b/random/Android.mk
index f17b621..5221265 100644
--- a/random/Android.mk
+++ b/random/Android.mk
@@ -10,10 +10,10 @@
 LOCAL_SRC_FILES += host/main.c
 
 LOCAL_C_INCLUDES := $(LOCAL_PATH)/ta/include \
-		$(OPTEE_CLIENT_EXPORT)/include \
+		    $(OPTEE_CLIENT_EXPORT)/include
 
 LOCAL_SHARED_LIBRARIES := libteec
-LOCAL_MODULE := tee_example_random
+LOCAL_MODULE := optee_example_random
 LOCAL_MODULE_TAGS := optional
 include $(BUILD_EXECUTABLE)