Revert "Prefer ARGB pixel format."

This reverts commit 6bb1e4c639e347cae1489cac1d500dc6d797e12c.
Merge branch 'texture' of https://github.com/christopho/solarus into texture
Revert "Revert "Prefer ARGB pixel format.""

This reverts commit 119cd71025aea465ed52e3619d5c1f521886db22.
Don't rebuild the texture when update it
Merge branch 'texture' of https://github.com/christopho/solarus into texture
Merge branch 'texture' of https://github.com/christopho/solarus into texture
Merge branch 'texture' of https://github.com/christopho/solarus into texture
Merge branch 'texture', remote branch 'origin/master' into texture
Merge branch 'texture' of https://github.com/christopho/solarus into texture
Fix the pixel mask for software surface
Move the global pixel format to use into VideoManager