Auto build and deploy documentation

S-01724

As a ExSeisDat Developer I want the Doxygen documentation automatically built and deployed on GitHub so the documentation is available and up to date.

PreDev Notes:

Using Travis CI integration with GitHub, it should be possible to add a script to build the docs, then add them to a GitHub Pages repo for ExSeisDat, likely at ichec.github.io/exseisdat, whenever a push is made to the devel branch.

Implementation Notes:

ADDME

System Test Changes:

ADDME

Bug Fixes:

ADDME

C++ API Changes:

ADDME

C API Changes:

ADDME

Success Criteria:

Pushing code to the devel branch automatically builds and updates the online documentation for the head of the devel branch.

CREATED ON 08/05/2018