change behaviour copying to clipboard

[xorond]

program should keep working if pandas fails to import, since copying to clipboard is more like an optional feature (some systems don't have methods for handling clipboard options, for example the virtual machine i used for testing the script).

we could also implement this behaviour in view:

• show the password on screen for a limited amount of time (~10s by default, maybe configurable through a flag)
• try to paste it to clipboard
• when timer runs out, clear clipboard as an extra security feature, to minimize the timeframe where the unencrypted password is stored in memory/clipboard
• clear the terminal screen

@Alex6312, please take a look at this

[Alex6312]

I changed the view function: It now tries to paste the password to the clipboard and only if this fails the password is printed in the console. Additionally after pasting to the clipboard the clipboard the program asks the user to press enter to clear the clipboard again. I think this provides sufficient security.

[xorond]

i think we should still show the password only for a given amount of time on screen (let's say default 10s) and then clear the terminal screen (the 'how' is dependent on is_posix) before quitting.

[Alex6312]

I made more changes to the view function: If a password is shown the program waits for the user to press enter and then it clears the screen. (I hope the command I used: os.system("reset") is the correct one for Linux.)
If you think waiting a fixed amount of time is better you the input commands with time.sleep(number of seconds to wait) instead.