added macros and concurrency chapter

Author: sn99

book/FontAwesome/css/font-awesome.css

@@ -352,7 +352,7 @@ function playpen_text(playpen) {
 
         var previousTheme;
         try { previousTheme = localStorage.getItem('mdbook-theme'); } catch (e) { }
-        if (previousTheme === null || previousTheme === undefined) { previousTheme = 'light'; }
+        if (previousTheme === null || previousTheme === undefined) { previousTheme = default_theme; }
 
         try { localStorage.setItem('mdbook-theme', theme); } catch (e) { }
 
@@ -364,7 +364,7 @@ function playpen_text(playpen) {
     // Set theme
     var theme;
     try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
-    if (theme === null || theme === undefined) { theme = 'light'; }
+    if (theme === null || theme === undefined) { theme = default_theme; }
 
     set_theme(theme);
 

book/FontAwesome/fonts/FontAwesome.ttf

@@ -63,9 +63,12 @@ a > .hljs {
     margin: 0;
 }
 
-#print-button {
+.right-buttons {
     margin: 0 15px;
 }
+.right-buttons a {
+    text-decoration: none;
+}
 
 html:not(.sidebar-visible) #menu-bar:not(:hover).folded > #menu-bar-sticky-container {
     transform: translateY(-60px);