Revert "Fixed issue with incoming e-mails decoding"

This reverts commit 29e3eac5010db94897e7eccedbbfc2c33288c62b.

Conflicts:
	README.md
Revert "Fixed broken processing of incoming e-mail attachments and multipart messages. Added filter that removes S/MIME signature files from attachments."

This reverts commit f2e4b0de58f17ed5946c7ed49b4c41618fb0e9a7.
Update paperclip to latest 2.x version

Fixes error in `identify`:
```
identify.im6: unable to open image `file': No such file or directory @
error/blob.c/OpenBlob/
```
Rails: Update to 3.0.20

Closes #11
It doesn't seem to break more (already broken) specs