Move description from textbox to icon in NamedItemView

[cneumuel]

Instead of the textbox which takes up a whole line, put an icon right next to the name textbox. The tooltip of the icon should reveal the description and additionally a doubleclick should open the TextDialog showing the description.

[swagner]

Added additional VS image library icons in r5827.

[swagner]

Changed NamedItemView and adapted derived views in r5832.

[mkommend]

Thx for implementing this elaborate feature. The only line I don't understand completely is the follwing (NamedItemView.cs):

private readonly string nl = Environment.NewLine;

In my opinion this is redundant and senseless to redefine the NewLine constant.

[swagner]

Thanks for reviewing.

Removed new line string constant in r5833.