Build EnclaveWrapper library using make package

Use ./app to test

Before compiling, you need to generate a private signing key under Enclave/Enclave_private.pem Correctly buliding EnclaveWrapper in Hardware Mode requires a SGX ready machine, installing SGX SDK&PSW and using a PSW version of libsgx_urts.so . This is rather tricky so you better ask @kss-espeo for help.