Fixes yeoman issue with hyphen in directory name

This fix basically replaces yeoman's replacement of special characters with spaces, with hyphen. There is an issue filed against yeoman which they closed with a refusal to fix.

Issue: https://github.com/krakenjs/generator-swaggerize/issues/5
Yes. Yeoman replaces anything not alphanumeric with a space. Since the default is a directory name, and there is no way to know what yeoman replaced, a hyphen is the next best thing to normalize the `appname` to a correct value.