Added Citra, A Nintendo 3DS emulator

[ivan-hc]

Hi, I have some tips:

• the icon must be a 128x128 PNG file, this for various reasons, including the resizing of the icons in the markdown and to avoid making the "apps.md" page too heavy, as it is already too full of objects to load... I could choose to make them even smaller, but later they would lose their aesthetics, also because they would be too small to see and the -i option of AM/AppMan, if it does not detect files in the "./icons" folder of the app, tries to download it from here, to be safe;
• the lines in the "citra.md" page are too long. For a Markdown to be displayed on the internet they are excellent, but not for a terminal window (AM and AppMan -a option);
• try not to load the other files too, that should be the task of the am2pla-site script which also generates the README.md with the updated count of apps available in the database. Usually I do this step, and only after that the -l option detects the new number of applications, and the -q option finds the new app.

EDIT: in fact, in the apps.md file you forgot to add the new digit.

Having said that, in summary try to only upload:

• the image (a *.png file measuring 128x128);
• the app page (the description lines start with a single space and must be a total of 80 characters or less in length to be displayed well in the terminal).

[ivan-hc]

@nazdridoy this is what I've corrected in this PR https://github.com/Portable-Linux-Apps/Portable-Linux-Apps.github.io/commit/836c2c0d63f8dee6f32380944f80876efc8e0f48

[nazdridoy]

got it.

for now i would leave anything other than $APP.md files to you. as you are automating the update process.