use cell size rather than window to calculate image view area

[iambumblehead]

lots of changes here

• adds a "fail" function, returns error code and message
• removes an escape query call, to call instead on condition of environment
• removes "W H" format, uses "WxH" format everywhere
• moves esc query calls to occur at main function (allow to disable later)
• replace some camel-case names with bash typical snake case
• changed some variable names

possibly/likely changes need to be made for kitty