Add unit tests and compile with Travis and PlatformIO

[s-celles]

Hello,

Continuous integration / unit tests are probably a good idea to make sure this library work as expected.

PlatformIO could help

A .travis.yml file is required

language: python
python:
    - "2.7"

# Cache PlatformIO packages using Travis CI container-based infrastructure
sudo: false
cache:
    directories:
        - "~/.platformio"

env:
    - PLATFORMIO_CI_SRC=Examples/Cbor_Serialbuffer_send

install:
    - pip install -U platformio

    # Libraries from PlatformIO Library Registry:
    #- platformio lib -g install ...

script:
    #- platformio ci --board=uno --board=teensy31 --board=due --lib="."
    - platformio ci --board=uno --lib="."

and enabling Travis https://travis-ci.org/

More info
http://docs.platformio.org/en/latest/ci/travis.html

Kind regards