Rewrite for version 3.0.0
Bump version to 3.0.0.beta1
Rename HelperMethods to ViewHelper
Add shortcut helpers
Add cover image
Bump version
Bump version in readme

[ci skip]
Update cover image

[ci skip]
Add property helper
Sort tags
Bump version
Raise on old property definition
Add info on custom shortcut helper

[ci skip]
Add Ruby 2.1.0
Release 3.0.0
Merge branch '3.0.0'