CSS class name changes

fold is now the classname for the guttermarkers, foldOn for the on
variant, foldOff for off
We have a seperate gutter now for folds, called folds and no longer
dropping markers into the linenumbers gutter
Seperate fold gutter, CSS tweaks & for count fix

Seperate gutter & class added for folds
Change to class names - now fold, foldOn and foldOff
Tweaks to coloring on fold markers
For loop needs to redo fold markers for both the start line and for the
length of the text. This means we now get fold markers when pasting
lines of text
Set gutter to be min-width not width

This is so the gutter width expands for bigger line numbers, was
overlapping due to fixed width