Changes for 2.3.8

• Fixed SVG rendering of Pictures with source rects and some backgrounds and Shapes.
• TextBlocks with very small text will now measure below a width of 8. Textblocks with no text will still size themselves as 8 units wide.
• Fixed Diagram initialization when a DIV is specified before the DIV is sized.
• Fixed shadow rendering inside of TableRow and TableColumn Panels
• Fixed minimum size of objects with a non-None GraphObject.stretch
• Text editing now ignores keyboard events such as Tab during a composition session.