Incorrect markdown in CHANGELOG.md (<meta> tag example)

[jschleus]

In the file CHANGELOG.md one can find at line number 412 the following example HTML code:

* Added meta-refresh redirect support. eg. <meta http-equiv="refresh" content="0;url=../default/mail/index.html">. Only for non-spidering

That leads to unwanted effects if browsing the according rendered HTML file, since as example HTML code in a Markdown file the expression should probably embedded by ` characters:

* Added meta-refresh redirect support. eg. `<meta http-equiv="refresh" content="0;url=../default/mail/index.html">`. Only for non-spidering

That seems to avoid the probably unwanted refresh forcing a jump to a probably non-existing page.