DEB-6741

@sergiopereiraTT @kzhdev 
A new PR off the SlickGrid repo.  Please review.  It is the same fix that moves the styles to individual elements to avoid constructing a <style> element after initialization.
I am working on a fix for the spanned column for spread matrix.  All other widgets are tested OK.  Resizing widgets, moving and resizing columns are working fine too.  I thought to start the review process going first.  Thanks.