Confirmation (add safety)

[alex-bender]

This pull request adds a bit of safety to the roamer:

• From now roamer will not take any action without explicit approval
  Before command(s) execution user will be asked to confirm commands:
  Please indicate approval: [y/N] -- No is default behavior. From now user have to answer Yes, Y, yes or y or with any word which starts with y to confirm, or use anything else to deny.
• This behavior could be discarded by passing argument --skip-approval. The roamer will execute all the commands generated after exiting editor.
• Whilst the prompt is displayed -- pressing Ctrl+C will discard any command(s) and exits the roamer.

Tested on Debian 8

[alex-bender]

@abaldwin88 Hello! I've created a new PR, please let me know if you want me to make any changes.

[alex-bender]

Please check my last commit

[alex-bender]

If you'd like this commit -- it's needed to add ignore rule to pylint

pylint roamer tests
************* Module roamer.session
W: 17, 4: Redefining built-in 'input' (redefined-builtin)
C: 17, 4: Invalid constant name "input" (invalid-name)

[abaldwin88]

Yea I'm ok with that. You can disable those checks for that specific line.

[alex-bender]

• [x] Done