core/issues/955, Total Amount includes the Tax amount twice

Allow handling of line items with no price field.

Fix validation error on Batch import

Fix a typo for the lineItem tax_amount

Fix case for CalculateLineItemFields.tpl include on Add and Edit tpls.

Not everything that creates line items associates them with a price field.
Assume these are quick config and set the quantity as int.

CIVICRM-868: Hiding tax field on edit line item form if no tax collected.

Add ability to add line items to line item edit

issue#17 Changing line_item quantity and unit price doesn't affect tax amount on both Add and Edit form

I suggest bumping to 5.x for clarity for people looking to install

issue#17 Changing line_item quantity and unit price doesn't affect tax amount on both Add and Edit form

LCD-29 : Unit price for text fields should be modifiable

LCD-30 : Line item changes should update connected participant fee total

LCD-28: $0 value line items should be allowed