Add application specific color constants.
Turn echo off in Windows command script.
Add memory functions. Move ? function handler into custom_operator. Remove help function handler. Improve help display by using two columns and taking console width into account.
Use app-specific color constants. Use result of execute method instead of rereading the stack.
Consistently use the word register instead of memory.
Reformat the array of hashes containing the collection of valid operators..
Add capability to print extra text not to be interpreted as operators before and after the operators list when displaying help.