Refactor rename the PixelASCII to CharPixel

fixed the go lint issue

Add method to support convert image to pixelASCII matrix

fixed the lint issue

Refactor the code to match the oop mode for easy mock and test

add the fit options to scale the image to fit the screen

Fxied the fetched wrong image width and height issue

add reverse options

Revert "add parallel convert"

This reverts commit 6ee682ae1c41bfd64968d71334d72b52c8d29ca3.

add parallel convert

Add some convert to fixed the lint issue

add main test case

add convert test case

refactor the convert package

Fixed a slice allocate issue

Rewrite the go docs

fixed the comment

add colored the asicc output

Add the method to fit the screen

add new method to convert a image from filename directly