Clear ansi-colored output

[nadevko]

1. When characters in the row have the same color, will be better print escape code only once: \e[38;5;20mw\e[38;5;20mm -> \e[38;5;20mwm
2. Use only space as invisible character, when background and text have same color: \e[38;5;0m<char> -> \e[38;5;0m

Also, will be cool mixing --color and --color-bg. Maybe, in form --color=(fg|bg|both)

[TheZoraiz]

Looks like too much work for too little gain. There aren't any significant performance improvements, and it would just make the code a readability nightmare (more than it already is...). I also can't accept the flag alteration request as too many projects depending on ascii-image-converter will break.