Added tests

[acecilia]

Added test suit based on ceedling.
Added makefile for easy execution of the tests.

In order to run the tests:

• Install ceedling in your system (ex: in mac just do gem install ceedling).
• Run make test from the root directory.

The main highlights of this PR are:

• Fix to FIFO.h
• Tests created in test/tests/test_FIFO.c
• Ceedling configuration file: test/infrastructure/project.yml
• The rest of the contents in the infrastructure directory are autogenerated by ceedling (executing ceedling new infrastructure)

[acecilia]

@geekfactory ?

[geekfactory]

Sorry, will try to check this out and include this on the master branch, however I´ve never used ceedling so I should try it with your pull-request.