[ADD] attachment_preview
[FIX] pep8
[ADD] use libmagic or mimetypes to detect a file's type
[FIX] typo
[RFR] move functions to module scope
[RFR] allow to get any binary field's extension
[ADD] allow previewing binary fields
[ADD] support old CentOS' magic module
[FIX] handle empty binary fields correctly
[FIX] remove old magic's charset detection
[FIX] support old firefoxes not implementing window.location.origin
Merge pull request #15 from hbrunn/6.1-attachment_preview

[ADD] attachment_preview