The buttons are created in the JavaScript. The simplest method to remove them would be to hide them using this CSS:
#wmd-code-button-content, #wmd-heading-button-content { display: none; }
To fully remove the buttons, look in the file Markdown.Editor.js in the function makeSpritedButtonRow() and delete the appropriate line, e.g. the lines starting buttons.code or buttons.heading for the buttons you circled.
Then you'll need to put the 3 JS files together (Markdown.Converter.js, Markdown.Sanitizer.js, Markdown.Editor.js) and minify into markdown.min.js.