form-actions class similar design in twitter bootstrap 3

You can use the form-horizontal class in bs3 also. However, major change is you have to define col width to the label as well as instead of using form-actions you can combine more buttons inside col-x-x class which used as controls in bs2. Please see this.

<form class="form-horizontal" role="form">
  <div class="form-group">
    <label for="inputEmail3" class="col-sm-2 control-label">Email</label>
    <div class="col-sm-10">
      <input type="email" class="form-control" id="inputEmail3" placeholder="Email">
    </div>
  </div>
  <div class="form-group">
    <label for="inputPassword3" class="col-sm-2 control-label">Password</label>
    <div class="col-sm-10">
      <input type="password" class="form-control" id="inputPassword3" placeholder="Password">
    </div>
  </div>
  <div class="form-group">
    <div class="col-sm-offset-2 col-sm-10">
      <div class="checkbox">
        <label>
          <input type="checkbox"> Remember me
        </label>
      </div>
    </div>
  </div>
  <div class="form-group">
    <div class="col-sm-offset-2 col-sm-10">
      <button type="submit" class="btn btn-primary">Sign in</button>  <button type="submit" class="btn btn-default">Cancel</button>
    </div>
  </div>
</form>

The .form-action is removed in bootstrap 3. and you can use a form-group to add the buttons at the end of the form.

You can add more buttons to form-group in the same line:

<div class="form-group">
        <div class="col-sm-offset-2 col-sm-10"> 
            <input type="submit" class="btn btn-default btn-lg" value="Save" >
            <input type="submit" class="btn btn-default btn-lg" value="Update" >
        </div>
    </div>

If you want to have some color effect or background color for the buttons, you must consider that the form-group has a left and right margin of -15px.

<div style="background-color: black; margin-left: 0px; margin-right: 0px;" class="form-group">

Please see Bootstrap 3 form and form last row background color