tests for install script

[vsoch]

We should have tests on travis to make sure the install is functioning as it should. @ArangoGutierrez

[vsoch]

ok, Docker setup is relatively sound, @ArangoGutierrez here is the list of todos if you want to take charge of anything!

• get base tests working
• addition of --prefix specification, and testing
• testing of install then selftest
• testing of development functions
• addition and testing of a clean function
• add cache to testing so we don't need to always rebuild docker images
• add remaining OS to tests

[ArangoGutierrez]

Sure I'll.
TO DO = fun homework