Play nice with MacOS

Solves #19
This breaks the tests because whitespace names become valid. See https://travis-ci.org/mfaerevaag/wd/builds/35351183

I don't have an OSX  machine available to test on, but what happens if you change this line to 

    elif [[ $point =~ "[[:space:]]+" ]]

to use a proper whitespace check? You can run the tests from the `/test` directory by running `./tests.sh`. Thanks!