file tree breaks on OSX when folder with folder icon is used

[kromeyer]

Description

Brackets file tree isn't working on OSX if folder with changed folder icon is opened. OSX creates an Icon file inside a folder if the user changes the folder icon or software like BTSync or Dropbox are in use which create specific folders and also use the icon mechanism.

Steps to Reproduce

1. create a folder
2. change folder icon (more details here: https://support.apple.com/kb/PH22191)
3. open brackets
4. open created folder in file tree view
5. an error will show up in console and the file tree isn't working anymore

Versions

OS Version: OS X 10.11.6 (15G1004)
Brackets Version: Release 1.7 Build 1.7.0-16898 (release b0a363b)

[petetnt]

Also reported in #12694 and #12703.

As this seems to affect many users, giving this a higher priorty

[petetnt]

Fix pending at #12807

[petetnt]

Fixed in #12807