Add CRT functions to runtime

[CHiPs44]

cf. https://www.freepascal.org/docs-html/rtl/crt/index-8.html :

Procedures & functions:

• AssignCrt Assign file to CRT
• ClrEol Clear from cursor position till end of line
• ClrScr Clear current window
• CursorBig Show big cursor
• CursorOff Hide cursor
• CursorOn Display cursor
• Delay Delay program execution
• DelLine Delete line at cursor position
• GotoXY Set cursor position on screen
• HighVideo Switch to highlighted text mode
• InsLine Insert an empty line at cursor position
• KeyPressed Check if there is a keypress in the keybuffer
• LowVideo Switch to low intensity colors
• NormVideo Return to normal (startup) modus
• NoSound Stop system speaker
• ReadKey Read key from keybuffer
• Sound Sound system speaker
• TextBackground Set text background
• TextColor Set text color
• TextMode Set screen mode
• WhereX Return X (horizontal) cursor position
• WhereY Return Y (vertical) cursor position
• Window Create new window on screen.

Constants:

• Black Black color attribute
• Blink Blink attribute
• Blue Blue color attribute
• Brown Brown color attribute
• BW40 40 columns black and white screen mode
• BW80 80 columns black and white screen mode
• C40 40 columns color screen mode
• C80 80 columns color screen mode
• CO40 40 columns color screen mode
• CO80 80 columns color screen mode
• Cyan Cyan color attribute
• DarkGray Dark gray color attribute
• Font8x8 Internal ROM font mode
• Green Green color attribute
• LightBlue Light Blue color attribute
• LightCyan Light cyan color attribute
• LightGray Light gray color attribute
• LightGreen Light green color attribute
• LightMagenta Light magenta color attribute
• LightRed Light red color attribute
• Magenta Magenta color attribute
• Mono Monochrome screen mode (hercules screens)
• Red Red color attribute
• ScreenHeight Current screen height
• ScreenWidth Current screen width
• White White color attribute
• Yellow Yellow color attribute

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