"E-mail from address" is not used (site default is used instead)

I did a simple replace form site_mail to configured from mail (if is empty, we use site_mail instead)

I changed "E-mail form address" to another one that different than site email but it didn't work.

Changing priority because this form item are unusable.

Fixed email from bug and email from name

Fixed patch in #4 comment

Return-Path and Sender headers are also using From field in SMTP module settings now.

@pazhyn, the patch from #13 looks simple and efficient, thank you!

There are only 2 minor codestyle glitches which I propose to correct:

1) line 93:
// Set SMTP module email from

2) if you removing double empty lines at ##113, 114, would be nice to remove one at lines 104, 105 as well.

Except these 2 cosmetic issues nothing wrong found. Code was also manually tested.

@dpovshed, thank you for corrections.

#15 looks great, good to go!