code styles, readability & maintainability

I had reworked basically every line, as I wanted to make another plugin out of it a longer time ago. Now realized, that I could push it over to your repo as well. I slightly went over it again.

Tasks done:
 * Readability & code styling
 * hooked init into `plugins_loaded`
 * Moved all "moving targets" (like IDs, etc.) over to the PHP file to avoid touching the JS/AJAX file in the future.
 * Shortened basically all names and removed the `my*` parts to avoid conflicts with other example plugins
 * Added phpDocBlocks all over

Guess that's it...