add .travis.yml

same as .travis.yml from conda with PYCOSAT lines removed
hardcode verify_rpaths to True: always verify rpaths
refactor resolve_link_error_handler

to make it exlicit we're calling import_name_from_module
Remove unneeded apt-get lines from .travis.yml
Don't install in .travis.yml

py.test doesn't like it for some reason.
Merge pull request #197 from conda/travis

add .travis.yml
Merge branch 'master' into rpath