Change realurl autoconfig

[klodeckl]

At the moment there is the following line in the default.php for the realurl config:
$TYPO3_CONF_VARS['EXTCONF']['realurl']['_DEFAULT']['fileName']['defaultToHTMLsuffixOnPrev'] = 1;

This is bad for installations which don’t use the html suffix, like I do. On that system I have four websites and two of them had .html suffixes when I installed the extension so I had to search to find out the problem.

Second it would be good to have a checkbox in the extension settings if you would use the realurl autoconfig or not.