Make Phone frame more beautiful

[scriptPilot]

• [ ] Show scrollbar only on scroll event, lighten gray
• [ ] Transition for frame / no frame

Phone frame, classes (previously):

• this.$$('html').addClass('pixel-ratio-2')
• this.$$('html').addClass('ios-gt-8')
• this.$$('html').addClass('light-scrollbars')

Planned three classes:

• limit-width

• limit-height

• phone-frame

• [ ] Show dark background after app initialization