improvements

• sop/text: allow to have each letter in a separate object. Each object will also be added attributes character, characterId and lineId.

bug fix

• sop/circle: remove 30 degrees rotation that was added to make the circle work easily with the hexagon grid. This proved to create other problems in basic circle usage.
• post/texture: add a temporary texture when the node is created, so that the render look does not error when the requested texture is not yet loaded.