Fix installation

In recent Node versions there is a `finish` event on Writable stream (http://nodejs.org/api/stream.html#stream_event_finish), but there is no such event in 0.8. However, `close` (http://nodejs.org/docs/v0.8.6/api/stream.html#stream_event_close_1) apparently works for all versions.

Without listening on `close`, promise chain aborts on `copyIntoPlace` without any notice, therefore following functions, such as `fixFilePermissions`, are never executed.

Fixes #9 and supersedes #10. Added [TravisCI](http://travis-ci.org/) for testing of installation.