Parallelise Travis builds across virtual machines
Parallelise Travis builds across virtual machines

See https://docs.travis-ci.com/user/speeding-up-the-build/#parallelizing-your-builds-across-virtual-machines,
and also https://docs.travis-ci.com/user/customizing-the-build/

Signed-off-by: Anurag Priyam <6e6ab5ea9cb59fe7c35d2a1fc74443577eb60635@gmail.com>

yeban/sequenceserver,yeban/sequenceserver,yeban/sequenceserver,yeban/sequenceserver