add drawing tools to videopaint

[Jheronymus]

The videopaint needs an onscreen (local) toolbar with at least:

• clear all
• clear own lines
• color selector
• brushsize

[rikkertkoppes]

Why not add them to the generic tools? By exporting more methods. Shortcut keys can also be added by the keybindings module

[Jheronymus]

In an ideal situation the 'tool palet' is only visible on the drawing device. This might be done by adding a small visible handle that can be clicked to expand.