Improve usability of the new TextField

The new TextField

• #19

When #19 is finished:

The textfield will support basic MineCraft 1.12 Written Book style edition (no cursor movement no selection). This is of course a dearly needed feature. To support this we need to make some change to the Client interception of UI input.

Required changes:

• Intercept special KeyInputs (like CTRL + V, and CTRL + C) on the client side and process them.
• Add support for cursor positioning (move the cursor by clicking) on the client side due to the requirement of the FontRenderer.
• Intercept special KeyInputs (like Left-Arrow, Right-Arrow) on the server side and process it accordingly.
• Add support for selection. Just as with cursor movement selection requires MouseInput to be tracked on the Client side.
• Add support for SpecialKey input syncing. Track SHIFT, CTRL and other special keys when messages are send to the server.
• Add support for special special KeyInput selection (like SHIFT+Left Arrow). This can be processed on the server side.

Start by reviewing issue #19 and the new TextField work described here. Trace client UI input, FontRenderer-related cursor positioning, MouseInput tracking, and the corresponding server-side key handling. Done means supporting clipboard shortcuts, cursor movement, selection, modifier-key syncing, and special-key selection for Minecraft 1.12-style written-book editing.