Bugfix in Travis CI config
Bugfix in Travis CI config

Forgot a -d in sphinx-build options. Have to build inplace for nosetests
to work.

drandykass/fatiando,santis19/fatiando,rafaelmds/fatiando,drandykass/fatiando,eusoubrasileiro/fatiando_seismic,eusoubrasileiro/fatiando,fatiando/fatiando,eusoubrasileiro/fatiando,mtb-za/fatiando,eusoubrasileiro/fatiando,victortxa/fatiando,cmeessen/fatiando,santis19/fatiando,rafaelmds/fatiando,victortxa/fatiando,cmeessen/fatiando,mtb-za/fatiando,eusoubrasileiro/fatiando_seismic,fatiando/fatiando