message: grpc: make readme more concise and readable
diff: +# DroneCore with GRPC
  -Use the following commands inside server folder to generate the CPP code:
  +## Prerequisites
  - $ protoc -I ../proto --grpc_out=. --plugin=protoc-gen-grpc=`which grpc_cpp_plugin` ../proto/dronecore.proto
  - $ protoc -I ../proto --cpp_out=. ../proto/dronecore.proto
  +### Install grpc
  -Use the following command inside python_client folder to generate the Python code:
  +Follow the instructions on https://github.com/grpc/grpc/blob/v1.6.x/INSTALL.md.
  - $ python -m grpc_tools.protoc -I../proto --python_out=. --grpc_python_out=. ../proto/dronecore.proto
  +### Install grpcio_tools for Python
  -Steps to run:
  -- make sure dronecore is already built and installed with below command
  - $ make default install
  +```
  +sudo pip install grpcio_tools
  +```
  -- Goto server folder and generate CPP files using above mentioned command
  -- Run make command to generate dronecore_server application
  -- Run PX4 sitl
  -- Run dronecore_server application, which connects to vehicle and listens to localhost:50051
  -- In another terminal, goto python_client folder and generate python files using above mentioned command
  -- Run dronecore_client.py
  -- vehicle takeoff and landing after 10 seconds will be observed on sitl
  +## Build
  -Things to Remember:
  -- unset http_proxy if anything is set
  +### DroneCore
  -## Prerequisites
  +```
  +make default install
  +```
  -###Install grpc
  +### Server
  -sudo apt install grpc # ?
  +```
  +cd grpc/server/
  +protoc -I ../proto --grpc_out=. --plugin=protoc-gen-grpc=`which grpc_cpp_plugin` ../proto/dronecore.proto
  +protoc -I ../proto --cpp_out=. ../proto/dronecore.proto
  +make
  +cd -
  +```
  -###Install grpcio_tools
  +### Python client
  +
  +To test Python client, start PX4 SITL, and run Python test script:
  +
  +```
  +./grpc/python_client/dronecore_client.py
  +```
  +
  +## Notes
  +
  +- `unset http_proxy` if set
  -sudo pip install grpcio_tools
  