Add Signature

Z 2 z 5 hwěžkow pohódnoćeny

wot Excelsior dnja Jan. 17, 2013 · trajny wotkaz

The add-on works only with signatures defined in the signature field of your account, which is too bad.
I managed to override the problem by copying the content of my file-sig in the thunderbird-integrated signature field, but that's not a pretty solution IMHO.

Please, add file-sig support, that'd be great.