Bonus emits 2 signals depending on winning or loosing

In previous version only the signal done() was send in
both cases making it harder to follow up in the activities.
Replaced hard coded activity list by a config file

Now the list of activities are set in the file:
src/activities/activities.txt

There is no more need to change ActivityInfoTree.cpp when a new activity
is added.
Improved scaling ratio

Now set the ratio to be calculated on our base reference size of
800x520.
Added many scaling where needed using the ratio.
The result is much better on tablets where many images was too small.
Fixed exit upon leaving 2 times in the same activity

We had a signal connection from the menu to the activity on the home
button. But when entered a second time another connection is done thus
the home is called twice and triggers the application quit.

In the patch we now pass the menu to ActivityBase and it triggers the
home and dialog box display.
Fixed an error message on home and dialog click.
Merge https://github.com/bdoin/GCompris-qt

Add ballcatch activity

Conflicts:
	src/core/Bonus.qml
Merge https://github.com/bdoin/GCompris-qt