CXX-74 enable clang support for travis-ci

This pull request successfully enables clang support for our build using Boost 1.49.

Also, currently testing output is cluttered with compile output so --quiet has been added to the compile flags. Check out how much nicer it is to look at the test results now.

Ideally we should have a two phase script that first builds all the necessary components of the project and a second which runs the tests so they are cleanly separated (and subsequently collapsed) so the test output is front and center.