Readme format update

Initialization is now in scope of WP init action

+ added WP_TRACY_ENABLE_MODE and wp_tracy_panels_filter

Update for Tracy 2.4

Added new get_queried_object() based panel

Změna min. stability: dev->stable

DOING_AJAX check

For IE compatibility WordPress media upload, thanks to @ViliamKopecky

Updated README screenshot

+ deleted asset(s)