Added class property pricerange

The absence of the property results in errors on line 590
Typo in comment
Prevent loop on empty array

Many messages show up in Shopp log due to undefined $taxrates, $settings when tax-settings have not all been set in Shopp admin. On installations 3 shopp-meta entries are added to database but they have no default value.
Set initial vaue for $labeling

If $label is empty an error will occur on line 962.
Preventing undefined array processing
Making sure $labeling has value
Merge pull request #3008 from Just-m/JM--2014-8-10

Code cleanup to prevent PHP NOTICEs in the logs