sig_analog: Add Last Number Redial feature.

[InterLinked1]

This adds the Last Number Redial feature to
simple switch.

UserNote: Users can now redial the last number
called if the lastnumredial setting is set to yes.

Resolves: #437

[InterLinked1]

cherry-pick-to: 20
cherry-pick-to: 21
cherry-pick-to: 22

[jcolp]

Why do this here in code instead of dialplan?

[InterLinked1]

Why do this here in code instead of dialplan?

If immediate=no, you can't easily capture the number dialed in the dialplan. It'll start executing it immediately so you'd have to have this logic at every extension, which is a complete mess.
I do this in my own code stack normally but on a "normal" Asterisk system this is really the only elegant way to do it.

[jcolp]

So yes it is possible.

[InterLinked1]

So yes it is possible.

No, not really, unless you have immediate=yes, which is the scenario to which I was referring. Otherwise this is too low level to be doable in the dialplan.

[jcolp]

I disagree, I believe it is reasonably possible for the usage of most users and wouldn't surprise me if others have done so. That's my opinion though and I won't stop this, others are free to join in and review this if they wish. I may eventually get around to it.