Prompt for input, read it, clean it, return it.

Changes for 0.005000

• Added -monitor option
• Added -prefill option
• Added -cancel option
• Added support for 'ansiNNN' and 'rgbNNN' colour specifications within -style and -echostyle arguments
• Improved error messages (some now indicate what the wrong argument was)
• Removed all uses of given/when and smartmatching for compatibility with Perl 5.38+