Add WPM counter
Slight clean up
Change background colour dependent on whether current wpm is on target
Simplify wpm update function
More subtle success colouring
Fix window-resizing issues
Increase text box font size
Consistent colouring over whole page
Reset wpm to zero if all text is deleted
Add not-writing colours
Improve word count functionality
Prevent instant failing mode when typing starts
Clean up colouring, move as much to css generation as possible
Add a submit button - currently doesn't actually do very much
Line up submit button with text area