astropy 3.0 requirement breaks python2.7 installl

Created by: ygrange

Whgen try to install LSMtool using setup.py, it will install astropy as a requirement. The astropy install for 3.0 rc1 fails to install in python2.7. As a quick fix I tweaked my local version the the setup.py to install_requires=['numpy','astropy >= 0.4, <3.0'],. That works for now. Not sure what the planning for the future is though.