Ignore progress events when the total file size is reported as 0 bytes (#475)
Ignore progress events when the total file size is reported as 0 bytes (#475)

Have tested this manually using the docs site. Wasn't able to reproduce a NaN value.

### Before
Drop a file
Progresses from 0 => 100%
Progress set back to 0% for a moment
Finishes

### After
Drop a file
Progresses from 0 => 100%
Progress stays at 100% for a moment
Finishes

Fixes #344


tim-evans/ember-file-upload,tim-evans/ember-file-upload