prompt for SMTP password instead of saving and showing it

[MrMaus]

Missing nearly nothing in this great software I am only unhappy with the configuration of the "sending email" feature as it shows the SMTP password in clear text.

It is clear that the password must be saved, so that automatic emails sending is possible. But I would prefer not to send any automatic emails and to prevent the possibility that someone takes a glance at the settings and checks my email server password.

So I did some coding (as described in the "Get Involved" section of the calibres web page) so that calibre will prompt for the SMTP password whenever the user is creating a send email job. If the option for prompting the password is switched on the automatic email sending is prevented.

The Pull request is created on github and the code awaits to be merged :-)

I would be happy to see this integrated into calibre although my implementation is not perfect.

(For example what is missing in my code: I failed to uncheck and disable all checked items in the account table in the email preferences dialog, when the Prompt Checkbox is checked by the user as I didnt find a way to access the table object.)

But maybe you find my implementation a good inspiration to do it better than me.

Thanx for this great software and a big

Oli