Add new callouts to docs

Created by: juthilo

Add callouts to the docs to make people aware that:

• Bootstrap does not support third-party JS libraries.
• Bootstrap only supports less.js for LESS compilation.

This pull request addresses #8288 (closed) and #8289 (closed).

@mdo I'm not sure if this is what you had in mind - wording is of course adjustable :).

docs/getting-started.html

@@ -48,6 +48,11 @@ lead: "An overview of Bootstrap, how to download and use, basic templates and ex
 <!-- Latest compiled and minified JavaScript -->
 <script src="//netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
 {% endhighlight %}
+
+    <div class="bs-callout" id="callout-less-compilation">
+      <h4>LESS compilation</h4>
+      <p>If you download the original files, you need to compile Bootstrap's LESS files into usable CSS. To do that, Bootstrap only officially supports <a href="http://twitter.github.io/recess/">Recess</a>, Twitter's CSS hinter built on top of <a href="http://lesscss.org">less.js</a>.</p>
+    </div>
   </div>
 
   <!-- File structure

docs/javascript.html

@@ -64,6 +64,11 @@ $('#myModal').on('show.bs.modal', function (e) {
   if (!data) return e.preventDefault() // stops modal from being shown
 })
 {% endhighlight %}
+
+    <div class="bs-callout" id="callout-third-party-libs">
+      <h4>Third-party libraries</h4>
+      <p><strong>Bootstrap does not officially support third-party JavaScript libraries</strong> like Prototype or jQuery UI. Despite <code>.noConflict</code> and namespaced events, there may be compatibility problems that you need to fix on your own. Ask on the <a href="http://groups.google.com/group/twitter-bootstrap">mailing list</a> if you need help.</p>
+    </div>
   </div>