Add support for variables in translation (#250)

templates/inc/footer.tpl

@@ -1,18 +1,40 @@
 </div>
 <footer class="small-font">
     <div class="footer_wrapper">
-     {t}Code by{/t} <a rel="author" target="blank"
-        href="http://rudloff.pro/">Pierre Rudloff</a>
-     &middot; {t}Design by{/t}
-     <a rel="author" target="blank"
-        href="http://olivierhaquette.fr">Olivier Haquette</a>
-     &middot;
-     <a rel="noopener" target="_blank" href="https://github.com/Rudloff/alltube">{t}Get the code{/t}</a>
-     &middot;
-     {t}Based on{/t} <a href="http://rg3.github.io/youtube-dl/">youtube-dl</a>
-     &middot;
-     <a rel="noopener" target="_blank" title="{t}Donate using Liberapay{/t}" href="https://liberapay.com/Rudloff/donate">{t}Donate{/t}</a>
-     </div>
+        {$dev="<a rel='author' target='blank'
+            href='http://rudloff.pro/'>
+            Pierre Rudloff
+        </a>"}
+        {t params=['@dev'=>$dev]}Code by @dev{/t}
+
+        &middot;
+
+        {$designer="<a rel='author' target='blank'
+            href='http://olivierhaquette.fr'>
+            Olivier Haquette
+        </a>"}
+        {t params=['@designer' => $designer]}Design by @designer{/t}
+
+        &middot;
+
+        <a rel="noopener" target="_blank" href="https://github.com/Rudloff/alltube">
+            {t}Get the code{/t}
+        </a>
+
+        &middot;
+
+        {$youtubedl="<a href='http://rg3.github.io/youtube-dl/'>
+            youtube-dl
+        </a>"}
+        {t params=['@youtubedl'=>$youtubedl]}Based on @youtubedl{/t}
+
+        &middot;
+
+        <a rel="noopener" target="_blank" title="{t}Donate using Liberapay{/t}"
+            href="https://liberapay.com/Rudloff/donate">
+            {t}Donate{/t}
+        </a>
+    </div>
 </footer>
 </body>
 </html>

templates/inc/header.tpl

@@ -5,7 +5,7 @@
                 {if isset($locale) AND $locale->getCountry()}
                     {$locale->getCountry()->getEmoji()}
                 {else}
-                    Set language
+                    {t}Set language{/t}
                 {/if}
             </button>
             <ul class="supportedLocales">