Clarify homepage hero and feature-card copy

Put open source in the hero lede, and make the first two cards describe
the benefit instead of listing scripting engines.

Author: ejboy

index.html

@@ -48,7 +48,7 @@
       <div class="hero__inner">
         <div class="hero__copy">
           <h1 id="hero-title">Lightweight ETL for Java</h1>
-          <p class="hero__lede">Scriptella runs SQL and other scripts against multiple data sources from one XML file. No visual designer, application server, or proprietary runtime.</p>
+          <p class="hero__lede">Scriptella runs SQL and other scripts against multiple data sources from one XML file. Open source. No visual designer, application server, or proprietary runtime.</p>
           <div class="button-group">
             <a class="button" href="tutorial.html">Two-minute tutorial</a>
             <a class="button button--secondary" href="download.html">Download 1.4</a>
@@ -81,11 +81,11 @@ <h2 id="overview-title">SQL for the work. XML for the wiring.</h2>
 
         <div class="feature-grid">
           <article class="feature-card">
-            <h3>Several sources, one file</h3>
-            <p>JDBC, CSV, text, XML, LDAP, shell, JEXL, Velocity, Janino, and more.</p>
+            <h3>Multiple sources, one file</h3>
+            <p>Work with JDBC, CSV, text, XML, LDAP, shell scripts, and other sources in the same ETL file.</p>
           </article>
           <article class="feature-card">
-            <h3>Existing SQL</h3>
+            <h3>Use your existing SQL</h3>
             <p>Run it directly, include files, bind query results as variables, and add expressions only where a transform needs them.</p>
           </article>
           <article class="feature-card">