Tiny bits of one-off code

• RPNGenerator.java -- Shunting Yard algorithm for converting infix to reverse polish notation
• Timer.hpp -- A general purpose stopwatch timer for software.
• count_pixels_canvas.html -- Count the number of black pixels on an HTML canvas that has an uploaded image
• send_email.go -- send emails straight from go by looking up the MX record then connecting to the SMTP server and sending.