ion-slide-box / ion-slide JS implementation

[ebryn]

• [x] make it kinda work: WIP in slide-box branch
• [x] fix swipe thresholds
• [x] improve animations
• [ ] pager
• [ ] slideshow/auto-play (will likely punt for our first pass)

attrs API: http://ionicframework.com/docs/api/directive/ionSlideBox/#api

[mattma]

@ebryn Is there an ETA for this feature? Thanks