Share & Remix panel updates.

This is the little panel that slides up with the orange tab.

Changes:
* Added QR code for sharing
* Added Email Remix link feature
* Added Email to Share feature
* Removed 'Install App' button when app is already installed
* Remix button opens a Email Remix popup when not on desktop

Tested on:
* Desktop Chrome
* Desktop FF
* Firefox OS
* Firefox on Android

vars inside for loops don't "expire", so after this runs, `i`, `p` and `closeme` are still real variables. Usually better to make that explicit by declaring them first: `var i, p, closeme; for(i=....`