Moving code to separate classes

[ghost]

This is the first PR for #231. I kept the commits as isolated as possible, to make it easier to review the changes.

This PR is not yet finished. I think it needs to be discussed first. All "old" tests are passing with this code. It also duplicates the capture-method I used in some other PR. I only added it to make the tests pass. The documentation is not complete. Tests needs to be written.

Besides that I'm quite happy with the code:

• It support's the old API and adds a lot of deprecation warnings
• Now all announcer code is bundled and has a nice API which be extended easily by us and by users - see a very first version of an example in lib/aruba/announcer.rb
• The announce_or_puts-method is gone and replaced by mode=
• I introduced a default_announcer which writes to /dev/null and an announcer which writes to what ever announcer was chosen by mode= - e.g. Kernel.puts, puts
• At first I thought it might be a good idea to store the activated announcers in a Hash, but decided against it because we would end up with different activated Announcers if the mode is changed between two activations
• All process monitoring code is bundled in ProcessMonitor - BTW I'm open to rename if one of you guys has a better idea.

@jarl-dk @mattwynne

Suggestions?

[jarl-dk]

I don't see the relation to the topics mentioned in #231. But never mind.

Regarding this PR: It seems like you have seen some light that haven't reached me yet and it will take some time for me to get there... I will just say that at first glance it all seems ok, for the rest of it I'll just trust you..

[ghost]

Merged into #257