Allow to use Bootstrap's split buttons for main menu dropdown

You can do this yourselve by overriding the hook_menu_link.
This is my version:

<?php
/**
 * Overrides theme_menu_link().
 */
function MYSUBTHEME_menu_link(array $variables) {
	$element = $variables['element'];
	$dropdown_link = '';
	$sub_menu = '';

	// On primary navigation menu, class 'active' is not set on active menu item.
	// @see https://drupal.org/node/1896674
	if (($element['#href'] == $_GET['q'] || ($element['#href'] == '<front>' && drupal_is_front_page())) && (empty($element['#localized_options']['language']))) {
		$element['#attributes']['class'][] = 'active';
	}

	if ($element['#below']) {
		// Prevent dropdown functions from being added to management menu so it
		// does not affect the navbar module.
		if (($element['#original_link']['menu_name'] == 'management') && (module_exists('navbar'))) {
			$sub_menu = drupal_render($element['#below']);
		}
		elseif ((!empty($element['#original_link']['depth'])) && ($element['#original_link']['depth'] == 1)) {
			// Add our own wrapper.
			unset($element['#below']['#theme_wrappers']);
			$sub_menu = '<ul class="dropdown-menu">' . drupal_render($element['#below']) . '</ul>';
			// Generate as standard dropdown.
			$attributes = array(
				'data-target' => '#',
				'class' => array('dropdown-toggle'),
				'data-toggle' => 'dropdown'
			);

			$dropdown_link = '</li><li' . drupal_attributes($element['#attributes']) . '>' . l('<span class="caret"></span><span class="sr-only">' . t('Toggle Dropdown') . '</span>', $element['#href'], array('attributes' => $attributes, 'html' => true));
		}
	}

	$output = l($element['#title'], $element['#href'], $element['#localized_options']);
	return '<li' . drupal_attributes($element['#attributes']) . '>' . $output . $dropdown_link . $sub_menu . "</li>\n";
}
?>

Optionally you can add something like this in your CSS:

@media (max-width: 768px) {
	.navbar-default .navbar-nav a.dropdown-toggle {
		float: right;
		margin-top: -40px;
	}
}

I would also love to see this happen, this would make dropdown menus very user friendly.

@BryanDeNijs : Is this solution applicable even on mobile devices?

Thanks,
Prathibha

Using this solution on mobile devices, on toggle touch only active menu item's sub links are shown but the siblings of active menu items will not be displayed

@prathibha.sn I wrote that code 3 years ago for D7. Not sure if it still works with the newest version(s).

Please read #1893532: [bootstrap][policy][7.x-3.x] Navigation/Menus, which I've just made a decision on.