Less verbose download stats for wget

Still shows download progress, but each dot represents a larger amount of data.

Reduces the console output from ~300 lines to ~10.
Use empty+nil instead of blank, fix issue with gp2 provisioning

- Replaces `blank?` with `empty? || nil?`
- Don't cast `nil` to `0` for `iops`, since the AWS SDK rejects `gp2` provisioning where an `iops` parameter is present.
Merge pull request #57 from sandstrom/iops

Use empty+nil instead of blank, fix issue with gp2 provisioning
Added .travis.yml, build status.
Removed extra # from readme.
Added rake dependency to test scope.
Fixed Rakefile for travis.
Update travis dependency to reflect cur stable.
Don't test on jruby.
relax version constraint on chef gem
Merge pull request #58 from airbnb/chef_version_constraint

relax Chef version constraint
bump version to v0.7.1
Merge pull request #55 from sandstrom/patch-2

Less verbose download progress for chef in bootstrap.sh
add CHANGELOG.md
Let Ohai know it's running on ec2

For more details, see:
https://github.com/opscode/ohai/pull/73/files
Merge pull request #56 from sandstrom/patch-3

Let Ohai know it's running on ec2
update CHANGELOG
expand path
Merge pull request #59 from airbnb/bug/expand_path

use File.expand_path
update CHANGELOG