Reverse Polish expression display gets cut off when they are too long

[Sean Kauffman]

The issue stems from using a statically allocated stack buffer for storing the growing, full expression. There is no real need to avoid using malloc here, apart from the desire to have it keep working on embedded platforms. Right now, though, it cuts off expressions when they get too long which they tend to do quickly.

[Sean Kauffman]

Fixed in commit 826b14f