Escape html

Hello ! I noticed several faults in escaping html through grapesjs some of it can be fixed by this pull request https://github.com/artf/grapesjs/pull/676 , but I still having problems with the html inserted on start.

In the example bellow the first <pre> is not rendered properly and I need to double escape it like on the second <pre> to get it properly rendered and be able to import/export after that properly.

Somehow between the several transformations applied to the initial html it get screwed.

			<div class="buttons">
				<h1>Buttons</h1>
				<a class="btn smooth btn-a">btn-a</a>
			
				<br><br><pre>&lt;a class="btn btn-b smooth"&gt;btn-b&lt;/a&gt;</pre>
				<br>
				<a class="btn smooth btn-a btn-sm">btn-sm btn-a</a>
				
				<br><br><pre>&amp;lt;a class="btn btn-b btn-sm smooth"&amp;gt;btn-sm&amp;lt;/a&amp;gt;</pre>
			</div>