Feature/541

[aranega]

Fixes #541

The color picker is removed from the "hover menu" and is integrated directly in each tree item.
Some setIntervals that didn't have the expected behavior have been removed.

Regarding the color update, it follows this behavior:

• if a color is assigned to a leaf, only the color for the leaf is changing;
• if a color is assigned to a container node (node with children), all the direct children inherit of the color;
• if a color is assigned to a leaf and among the sibiling of the leaf, there is one that hasn't the same color, the container node color passes as gray;
• following this policy, when random colors are given to a container node, the container node color is gray while all children have their dedicated color.