WordPress GitHub Sync by James DiGioia, Ben Balter (WordPress.org)
Description A WordPress plugin to sync content with a GitHub repository (or Jekyll site) Ever wish you could collaboratively author content for your WordPress site (or expose change history publicly and accept pull requests from your readers)? Looking to tinker with Jekyll, but wish you could use W...
Prevent wp_debug from polluting ajax within plugin (WordPress Development Stack Exchange)
I've ran into an issue here where wp_debug notices foul up my ajax response. The codex suggests using ob_clean just before returning or echoing: To parse AJAX, WordPress must be reloaded throug...
If you have php notices turned on, bad things happen.

Why Categorize when you have Post Kinds and Tags – Disabling categories in WordPress

Consider putting all your changes in a child theme. Look at my child theme as an example.

add to functions.php in your theme:

function dougbeal_unregister_categories() {
    register_taxonomy( 'category', array() );
}
add_action( 'init', 'dougbeal_unregister_categories' );
unregister_widget( 'WP_Widget_Categories' );

https://wordpress.stackexchange.com/questions/120418/completely-disable-categories
http://stackoverflow.com/questions/4249694/how-do-i-remove-a-taxonomy-from-wordpress