planegame, major rework

Mostly moved the javascript code in QML files to the planegame.js
planegame, added smooth animation for the helico.
planegame, added animation on clouds
clickgame, fixed reference to sizeTable.png
planegame, tuning, less random on clouds
planegame, added animation on plane size change.
planegame, added support to pass a dataset

Now the could's content are passed through a dataset in Sequence.qml.
This open new usages for this activity.
Added new activity to learn odd and even numbers.

This activity is based on planegame. Only a dataset is provided.
numbers-odd-even, minor, fixed copyright notice.
alphabet-sequence, new activity based on planegame.
core, Score can now be use to display a message

By writting to the message property instead of the levels one a
little message can be displayed.
planegame, improved the dataset to specify a showNext prop

The showNext property is used to specify if the next item to find
is displayed.
planegame, improved smooth of the plane at upper levels.
planegame, add an audio crash sound on wrong cloud.

Moved bonus.wav from planegame to core/resource/sounds
memory, minor edition of the menus.
click_on_letter: pass items in QtObject container
click_on_letter: adapt to current API for localized sound filenames
click_on_letter: add french levels file as POC for non-ASCII only levels
planegame, major rework of the animations

Replaced arrows in the mobile version by gesture on the helico to
move it.
Now the animation of the plane is smooth thanks to the
SmoothedAnimation.
Gcompris.pro: add algebra_plus, algebra_minus

Also add algebra_plus, algebra_minus to activities.txt