Jewel Support Part 3: Skill Tree UI

[brather1ng]

This adds jewel support to the skill tree UI. That includes:

• Socketed jewel icons are drawn.
• Tooltips of socketed jewels include the jewel item's tooltip and, if relevant to the jewel, the amount of allocated attributes in radius.
• For filled jewel sockets, only the radius, if any, of the socketed jewel is drawn. This radius is always drawn, not only when hovering over the socket.
• When hovering a socket, nodes in radius are highlighted. To better distinguish the different radiuses, each radius has a different color.
• The Equipment tab shows the skill tree area around a jewel when hovering over the item slot.
• Items can add connections to the passive tree, e.g. from Intuitive Leap. These aren't really added as actual connections, but they are handled correctly when skilling and refunding nodes.
• (not entirely related) Passive nodes allocated by items (e.g. Keystones from Uniques, annointed amulets) are displayed as active. Blighted notables have their correct node surround asset used.