Disable travis-ci auto-push to RubyGems
First pass at some integration testing

Tests that you can build a CentOS 6.5 Vagrant base box using the packer-config infrastructure. Setting this up caught some bugs in the packer-config code, so that's good, right?
Add a :clean task and exclude JSON files created by integration tests
Update example so it is a working example
Pretty print the JSON output
Make pretty print optional, handle paths on output files, implement delete

Fixes a problem with pretty print being always-on and testing.

Handle paths on the output file by changing to the path before running the packer commands.

Delete the JSON file after things validate or build successfully.
Add UTF-8 encoding line for Ruby 1.9.3
Bump version to 0.0.3