Add Buffer support to the default exported function

[valentindusollier]

Hi,

Thank you for your library 😉

I added support for Buffer to the default exported function. Most library which manipulate images allows to get buffer from their image instances, therefore you can use your function directly with these buffers without having to save the images on the disk:

imageSimilarity(bufferedImage1, bufferedImage2)

You can also use path and buffer in the same function call.

I translated the function rejection in English and let the Chinese version. I had to use Google Translation to add another promise rejection. Feels free to edit it. I did't change the Readme because it is only in Chinese.