Read a command line from the player. Displays the main command prompt and returns a line of input.

We process any pending real-time events before reading the command. If the local platform supports real-time command-line interruptions, we'll continue processing real-time events as they occur in the course of command editing.

Read a line of text and return the token list and the original text. We keep going until a non-empty line of text is read.

'which' is one of the rmcXxx enum values specifying what kind of command line we're reading.

The return value is a list of two elements. The first element is the string entered, and the second element is the token list.