Issue #423 - right sidebar push not working

- Change body.pushed to always use 'margin-left'
  - Invert margin to negative if its direction is right

src/modules/sidebar.js

@@ -202,13 +202,15 @@ $.fn.sidebar = function(parameters) {
         add: {
           bodyCSS: function(direction, distance) {
             var
+              invertDirection,
               style
             ;
             if(direction !== className.bottom) {
+              invertDirection = direction === 'right' ? -1 : 1;
               style = ''
                 + '<style title="' + namespace + '">'
                 + 'body.pushed {'
-                + '  margin-' + direction + ': ' + distance + 'px !important;'
+                + '  margin-left: ' + invertDirection * distance + 'px !important;'
                 + '}'
                 + '</style>'
               ;
@@ -218,6 +220,7 @@ $.fn.sidebar = function(parameters) {
           }
         },
 
+
         remove: {
           bodyCSS: function() {
             module.debug('Removing body css styles', $style);