Improvements for buttons

[SamyPesse]

• [x] Remove .btn-fill, buttons are filled by default
• [x] Add btn-text-{style} to replace previous default state
• [x] Remove btn-default
• [x] Add btn-plain for flat buttons
• [x] New btn-outline
• [x] btn-count replace btn-outline

[AaronO]

Remove .btn-fill, buttons are filled by default :+1: