Add tutorial code and fix namespace xaml.converters name.

Signed-off-by: Maxence Charriere <maxence.charriere@outlook.com>
Add files

Signed-off-by: Maxence Charriere <maxence.charriere@outlook.com>
Merge branch 'master' of https://github.com/Oblo/Smile
update

Signed-off-by: Maxence Charriere <maxence.charriere@outlook.com>