update .travis.yml to exclude math/ for now, add 1.7
update .travis.yml to exclude math/ for now, add 1.7


Former-commit-id: 099b81cbb87aa4d01476275e0bc126407f45dfae [formerly 3758827a5cd9bca3e07e6387f90e7ff37f959223]
Former-commit-id: af8d9fa2a03a4acc7fa8bbd119a8e0fed8d54c80
EricLagergren/decimal