Ask to enter presentation mode.

Ask to enter presentation mode.

If you deactivate screensaver (ie: move mouse) or unlock desklock
within some given threshold, ask user if he would like to enter
presentation mode or even if should increase timeout to next event.

This is also useful when at the office and you quickly move mouse in
order to keep your explanation. If you know your explanation is short,
just hit "increase timeout", otherwise "Yes" to increase timeout.

Increase timeout is a multiplier that will increment the factor on
each dialog answer.

There is an option to stop asking. This can be changed in "Advanced"
versions of screensaver and desklock dialogs.

SVN revision: 40414