Add new type of hooks

Also fix some default values lookup issues
Fix #5732 - Refactoring of exit code

The logic around exit code was extracted to new class. You can still
trigger exit using KafoConfigure.exit(code, &block) call. We also log
the exit code.
Fix #4959 and fix #3224

Log messages are buffered and log once again when Logger is setup. Also
we keep all errors and repeat them at the end if the process fails.
Add custom configuration storage
Enable progress bar with Puppet 3.6
Version bump
Merge pull request #86 from ares/new

New features and new version bump
Automatic commit of package [rubygem-kafo] minor release [0.6.0-1].
Fixes Markdown typo in README.md
Merge pull request #87 from spuder/patch-1

Fixes Markdown typo in README.md
Add contribute information to README
Modernise and update spec file for EL7
Merge pull request #88 from ares/update_readme

Add contribute information to README
Merge pull request #89 from domcleal/el7

Modernise and update spec file for EL7
Automatic commit of package [rubygem-kafo] minor release [0.6.0-2].
Improve default values support for puppet 2.7