Updated Filesaver.js to the latest version.
Changed mime type of the bundle export blob to support Safari 7.
Merge pull request #174 from hatched/safari-blobs

To QA
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- Make sure that bundle export/import still works as expected in Chrome/FF/IE
- Bundle export from Safari. It should open the yaml in another tab. You will then need to cmd+s to save the bundle as a yaml file. 
- Import that bundle into Safari to make sure that it exports properly.

Notes
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The fix is in app.js.
The changes to Filesaver.js are simply an update to the latest version