Fix problems when saving prefs page in admin

Fix problems with prefs (sitedisclaimer, sitedescription, etc) when
inserting HTML code.

extra spaces here are causing two problems:

1 - back-end : each time you save one of those options it become longer
because of the extra space added...

2 - front-end : the toHTML() function add extra <br> code when it is not
needed ( ex.: when you have just one line it add a <br> before and after
the line. instead it should add <br> only when new line is found)

Fix #411, #471,