Canvas Text: Render text in HTML 5 canvas objects

This object can render text in HTML 5 canvas objects.

It can create a two dimension canvas object and renders text strings in it using given text style class definitions embedded in the text similar to HTML tags.

The style classes can include definitions for rendering parameters like the text font, color, size and text alignment.

The text style definitions can be cached to avoid the overhead of recomputing the text styles.