Merge branch 'hotfix/0.4.7'

* hotfix/0.4.7:
  improve button specs
  bump version to 0.4.7
bump version to 0.4.8
don't use disabled class for buttons - it has the attribute
Merge branch 'hotfix/0.4.8' into develop

* hotfix/0.4.8:
  don't use disabled class for buttons - it has the attribute
  bump version to 0.4.8