Fixes #141: do not attempt to load Berksfile if not present
Update slack.rb

add supporting of images into slack.
Add README changes
relax foodcritic version requirement

...from `~> 3.0.0` to `>= 3.0.0`

4.0.0 is out and both the docs and error message say `>=`. 4.0.0 is working fine for me with this change.
add support for rubocop >= 0.23.0

in 0.23.0 they renamed `Rubocop` module to `RuboCop`
updated instructions
spork promote to multiple environments
update README
pass whole config, not just cookbook_path

This was causing an issue (#140) because we were
passing an Array instead of a Hash.
Compare the two following links:

https://github.com/opscode/chef/blob/11.14.6/lib/chef/cookbook_uploader.rb#L39
https://github.com/opscode/chef/blob/12.0.0.alpha.1/lib/chef/cookbook_uploader.rb#L38
follow lamont-granquists suggestions
account for pre-releases, use >=
Update .ruby-version
remove puts
Fix for when custom_path is not defined.  on Windows this was causing the cookbook to not be bumped correctly, and was failing without an exception
Adding initial tests and travis config
Adding travis badge to readme
fixing travis badge
Correcting travis link
More tests for upload, bump and promote
Update travis config