#217: Add ISSN validator document
#216: Add ISMN validator document
#215: Add IMEI validator document
Move sample data to page attributes
Remove slug data
#213: Add EAN (International Article Number) validator doc
Update version and changlog (v0.4.4)
Update the changelog
#220: Add UK postcode examples
Add credit card example
Update the date validator doc
Release v0.4.4