Since Bootstrap is a very heavy project, including all its repositories is not actually required, and even if you do, this could put enormous load on your website, making it sluggish and affecting user experience. To get the Bootstrap engine suited to your specific needs, go to http://getbootstrap.com/customize/ and import a style file with the settings you need. You can also import your existing settings file on the preceding link, add or remove options within the GUI, and get an updated version without writing a single line of code.