2.05 : fix 3 issue with numeric question type (javascript and php)

See:
-* Comparaison String and Numeric is different in same page and other page : http://bugs.limesurvey.org/view.php?id=7805
-* "Numerical Input" question validation only client side : http://bugs.limesurvey.org/view.php?id=8217
-* Javascript autocorrection of numerical values : http://bugs.limesurvey.org/view.php?id=8247

Actually leave JS global var : easy to update in template or in survey (wthout XSS). But still need to go on 
-* Survey settings (Plugins): need to have a hook for getConfig
-* Question attribute (2.05 or 2.06 ?)

I put some "lss example file" on mantis next