the `licenses` field in package.json is deprecated. https://docs.npmjs.com/files/package.json#license

The `license` field is the recommended field and expects an SPDX expression.

Right now the package is not recognized as usable library by Browserify.
Adding the main attribute in the package.json solves that, and now gives
others the possibility to use reveal as a library in more complex
systems.

re-created unprefixed version of reveal.css automatically using autoprefixer, to facilitate merging of changes to it

- upgrade grunt-contrib-connect to ~0.5.0
- configure connect and watch plugin

Set targets to lint, and quint for when the testing is implemented

Was at ~0.3.2, but doesn't seem to have been released properly.