Direct upload

Direct upload to S3
Just need a ```directUpload: true``` option
Also solves the problem when the file is large and it takes longer than 35 seconds to upload it because of the 
[heartbeatInterval](https://github.com/meteor/meteor/issues/1861#issuecomment-56597170) 

```
Template. MyTemplate.helpers
  forProfilePic: ->
    directUpload: true
```
```coffeescript
### CORS configuration
<?xml version="1.0" encoding="UTF-8"?>
<CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
   <CORSRule>
        <AllowedOrigin>*</AllowedOrigin>
        <AllowedMethod>GET</AllowedMethod>
        <AllowedMethod>POST</AllowedMethod>
        <AllowedMethod>PUT</AllowedMethod>
        <AllowedHeader>*</AllowedHeader>
    </CORSRule>
</CORSConfiguration>
 
This tells S3 to allow any domain access to the bucket and that requests can contain any headers, 
which is generally fine for testing. When deploying, you should change the ‘AllowedOrigin’ 
to only accept requests from your domain.
###
```