Add documentation section to the README file

Merge pull request #5 from Tastyep/develop

develop #comment Add build status to the README.

develop #comment Use nanoseconds as default duration (Scheduler).

develop #comment Improve travis file format.

develop #comment Add a --cov option to configure.sh to enable coverage.

develop #comment Add findModule for Lcov and Gcov.

develop #comment Add external clang-tidy target to clone the repository when run-clang-tidy.py is not provided with the distribution pakage.

develop #comment Add a clang-tidy target.

develop #comment Add travis file for continuous integration.

develop #comment Test the scheduling status of a reunning periodic/normal task.

develop #comment Add code documentation to the project's API.

develop #comment Add TaskManager/ directory in include/ to avoid include directory problems.

develop #comment Add a clang-tidy configuration file.

Update the ReadMe file