This little stylesheet reverts new Bootstrap 3 button styles to the old ones, including .btn-inverse again.
The .btn-primary style is based on the Bootstrap 3 theme, but a .btn-old-primary was included with the old shiny blue primary button.
They are compatible with the new Bootstrap 3 buttons styles and have the new padding, to fit with other form controls.
Disabled, focused and active styles are supported, as well as .btn-lg, .btn-sm, .btn-xs and .btn-block.
Include one of the files located in the css folder (bootstrap-buttons.css or bootstrap-buttons.min.css) in your Bootstrap 3 project after bootstrap stylesheets to get the old styled buttons.
Alternatively you can install this package with bower by running bower install bootstrap2-styled-buttons
You can see this in action here.
The building process has been automated by using Grunt. Take a look at its documentation for more information.
The automation script just compiles the SASS stylesheets, creating a normal and a minified CSS stylesheets in the css directory.
It requires compass to properly work.