Strengthen the price attribute field value retrieval

"Number in stock" must not be considered as a price field just because
it has a " in " inside its label. Solution brought here is to check that
the field name ends with "in " followed by 3 uppercased letters (like in
"Price in EUR").
Strengthen the multi words label field retrieval

Labels may contain as many words a wishes. Only rule is that the first
word of the label must start with a label (otherwise it'll be considered
as the field scope).