Changing the name of forms classes

We think the name that we put in forms elements was very confusing. The
label was called .ls-field and the text of label was called ls-field.
Now, we chage this to this:
label is *.ls-label*
text of label is *.ls-label-text*
input/field is *.ls-field*
fieldset or another form container is *.ls-form-group*

We think this is better.