Fix coveralls

[wkerzendorf]

Fix the problems with coveralls. This should now work as expected

Added testing for three setups described in the .travis.yml file. This includes the new coverage.

[wkerzendorf]

@mdboom This is a semi-affiliated package of astropy (using the setup stuff of astropy). I implemented the changes to get coverage working. It now produces a .coverage file (https://www.dropbox.com/s/3c6ng6r25j9bvq9/coverage). When I look at the coverage file it only shows me lines in astropy that are covered - not in the TARDIS package (despite there being tests). Would it be possible for you to have a quick look? Thanks in advance

[mdboom]

pip install astropy doesn't install the recent changes to astropy master that are needed to make this work. You can have pip install astropy from git in your .travis.yml or wait for the next astropy release.

[wkerzendorf]

@mdboom Thank you. I hadn't thought about this.

[wkerzendorf]

@ssim @mklauser toughts? I'm ready to merge as soon as TRAVIS passes

[coveralls]

Coverage remained the same when pulling 0819976 on wkerzendorf:general/fix_coveralls into fe6723a on tardis-sn:master.

[coveralls]

Coverage remained the same when pulling 0f02a21 on wkerzendorf:general/fix_coveralls into fe6723a on tardis-sn:master.

[coveralls]

Coverage remained the same when pulling 6b27262 on wkerzendorf:general/fix_coveralls into fe6723a on tardis-sn:master.

[ssim]

Seems wise to me.