Improve PSCF development

[Gjacquenot]

This PR does several things:

• Convert Readme to Readme.md for a better presentation on GitHub
• Add the Travis Continuation Integration, to test compilation for each new commit
• Add a Dockerfile to test HOS-NWT from anywhere

The result of Travis CI can be seen here

If integrated, they are several steps to perform to benefit from these services on morse account

• Create Travis account, activate pact tracking
• Update Readme.md travis build status (at the end of file Readme.md)

[Gjacquenot]

Ping @dmorse

[dmorse]

Gillaume - Thank you for your help. I didn't reply for a while because I was ignorant about
both travis and docker. After looking at your changes, and reading a bit about these tools,
I decided that I should learn more and that the best way to do so was to accept your pull
request. Thanks once more for the unexpected help.