HPCC-10635 Replace @temp with atmark_temp

Replace @temp with atmark_temp for both file contents and directory name.
This help to workaround the problem introduced in cmake 2.8.12 which try to fix directory name with
"@" but didn't do it cleanly.

With above fix hpcc platform is built successfully on Fedora 19, 20 as well as all our supported Linux distros.
Also tested with some ECL samples on Fedora 19 and spray a file.

Add symbolic link @temp in install-init in Unix for backward compatibility. If it need done on Windows
a new JIRA ticket can be opened to address it.