Add dates to old projects

Author: Alexander Gauggel

docs/old-projects.markdown

@@ -7,7 +7,7 @@ layout: home
       <a href="/plain-renderer/">
         <img src="/images/Thumbnails/PlainThumbnail.jpg" alt="Plain thumbnail" />
         <div class="project-text-box">
-          <h3>Plain Renderer</h3>
+          <h3>Plain Renderer (2020-2021)</h3>
           <p>C++ Vulkan Renderer featuring advanced real time rendering techniques</p>
         </div>
       </a>
@@ -17,7 +17,7 @@ layout: home
       <a href="/software-rasterizer//">
         <img src="/images/Thumbnails/SoftwareRasterizerThumbnail.jpg" alt="Software Rasterizer thumbnail" />
         <div class="project-text-box">
-          <h3>Software Rasterizer</h3>
+          <h3>Software Rasterizer (2020)</h3>
           <p>C++ Software Rasterizer featuring multithreading and SIMD</p>
         </div>
       </a>
@@ -27,7 +27,7 @@ layout: home
       <a href="/opengl-renderer/">
         <img src="/images/Thumbnails/GLRendererThumbnail.jpg" alt="OpenGL Rasterizer thumbnail" />
         <div class="project-text-box">
-          <h3>OpenGL Renderer</h3>
+          <h3>OpenGL Renderer (2018-2019)</h3>
           <p>C++ OpenGL Renderer featuring basic real time rendering techniques</p>
         </div>
       </a>
@@ -37,7 +37,7 @@ layout: home
       <a href="/alamo-tools/">
         <img src="/images/Thumbnails/AlamoThumbnail.jpg" alt="Alamo Tools thumbnail" />
         <div class="project-text-box">
-          <h3>Blender Plugin: Alamo Tools</h3>
+          <h3>Blender Plugin: Alamo Tools (2017-2020)</h3>
           <p>Blender Plugin implementing import and export of Alamo-Engine models</p>
         </div>
       </a>
@@ -47,7 +47,7 @@ layout: home
       <a href="/other-projects/">
         <img src="/images/Thumbnails/OtherThumbnail.jpg" alt="Other projects thumbnail" />
         <div class="project-text-box">
-          <h3>Other projects</h3>
+          <h3>Other projects (2018-2021)</h3>
           <p>Various university and smaller projects</p>
         </div>
       </a>