gRPC-based Google API installation assistance for C++

Follow Google's guide to configure the system and run test.
Remember to create an App engine (e.g. Python)!
- Installation Order
  1. protobuf 3.1.0
  2. latest gRPC (not release version)
  3. Google APIs
use the Makefile to package and install the google APIs into the system for easier compilation:
```
 $ make
 $ (sudo) make install
```

(this Makefile is modified from the same guide)

Note

GOOGLEAPIS_GENS_PATH must be set correctly use ' nano ~/.bashrc' and add the following line to the end of the file :
```
 export GOOGLEAPIS_GENS_PATH=$HOME/path/to/googleapis/gens
```
This project is based on Visual Studio for Linux C++ development on Raspberry Pi and the other codes and configurations may not be suitable for use otherwise