Wordlist new XML properties for gletters & wordsgame

- Wordlist levels have 3 new, optional parameters:
-- fallspeed: how fast the words fall
-- speed: how fast a new item is dropped after the last one
-- sublevels: how many items are in the level

- gletters:
-- use the new parameters
-- display bonus at end of level

- wordsgame:
-- use the new parameters
-- display bonus at end of level
-- levels now start with a defined speed + fallspeed
   when the user clicks through the levels
falling letters: activated letter voice is now by default
falling letter: improved level sequence for french and english.
core sound: fixed a race around background music

This commit fixes a race condition that happens when we
start GCompris and enters an activity that mutes the
background music before the intro music is completed.

In this case, the intro music was not muted as expected.
hangman, minor translator comment update.
In 3 activities removed token in sentences to ease translation

It is not always possible to create a valid translation using
a {text} replacement token in a sentence because for example of
gender issues. This patch replaces such strings by the full
sentence.
Updated Czech translation
automatic translation update for advanced color

Since the advanced color string has changed and it is hard
to get them, I wrote a little script to port the old translated
colors in the new string format.
automatic translation update for advanced color

Since the advanced color string have changed and it is hard
to get them, I wrote a little script to port the old translated
colors in the new string format.
automatic translation update for advanced color

Since the advanced color string have changed and it is hard
to get them, I wrote a little script to port the old translated
colors in the new string format.
color mix, use full string message for colors

In many languages colors have gender and cannot be
translated out of their context.
Disambiguation of translation is now handled with the Q_ macro.

Added support for string disambiguation in shapegame tooltips.
Now in tooltip if the string is marked as "Asia|Georgia",
only the Georgia part will be displayed, the 'Asia' being
usefull for translators.

Added translation of USA states.
Improved message string for 'default'
Minor, replaced fixed font size to a GCompris one.
Separated scores into two strings for correct positioning.

Repositioned board bar.
minor, fixed text positioning
Replaced hardcoded font with fontset font
Implemented multigraph support
Gletters: slowed down levels for Scottish Gaelic
Using skin fontsets now