removed the other mention of cmath
add coveralls to travis config
Merge pull request #742 from wafels/fix_app_ra

removed the other mention of cmath
install coveralls
Merge branch 'master' of github.com:sunpy/sunpy
fix typo
add pytest-cov to install on travis
add coverage report to leading build
add coverage to whole build matrix
Add coveralls badge to README
add coveragerc, stolen from scikit-image
add pragma no cover @derdon