New Tool: Text Tool

[Keavon]

Clicking somewhere creates a Text Layer at that location and begins letting the user type. This translates to a <text> SVG tag on the canvas. While editing the text, the user can type stuff. Return is a new line but Enter (on the numpad) applies the text, as does CtrlReturn. The Text Tool also lets you click anywhere over an existing text layer and begin editing that text in the location clicked.

[0HyperCube]

@Keavon A few challenges with this:

• We need to find the length of glyphs (characters in the font) so we can place the cursor, find the bounds of the textbox and handle moving the cursor to the right place when clicking on existing text.
• Also we probably need to be able to convert text to a path (involving the backend parsing .ttf files or similar which could then also be put into a font attribute in svg - https://www.w3.org/TR/SVGTiny12/fonts.html - this would solve the glyph length problem above)
• We should probably follow OS preferences such as sticky keys (shortcuts for people with reduced motion), cursor blink speed / width as well as properly handling support for Chinese / Japanese / Korean.