support node-webkit 0.10.0-rc1 with refactored Travis CI builds

This is basically a request to merge `travis-refactor` branch to `master` and to publish new hosted binaries (for all of the supported platforms) and a new version of the npm package after that.

That branch seems complete (i.e. the Travis builds are refactored), it contains important improvements (such as a support for node-webkit 0.10.0-rc1), changes (such as the new AppVeyor ID) and bug fixes (it fixes #312, for example).