Shape of entered text block affects node drag

[l3td33r]

Make it easier to drag nodes.
If we click on a node text box, it usually starts editing text, which makes it hard to drag them. Especially, if almost the whole content of the node is text (then the only way to drag the node is to click on the node border, which usually takes a few tries, since it's only a few pixels wide).

It shouldn't start editing the text, but drag the node:

• click+drag on text box = drag the node
• click on text box = edit the text
• click+drag on text box while in text editing mode = select text (already works like this)

[juzzlin]

It is supposed to work like this, but it seems that there are some problems depending on the layout of the entered text. Another option to drag a node is to use the "drag handle" at the top left corner.