issue-291 fix date column sorting

See merge request !274

Don't require payment information for multiple participant event registration if all amounts are 0

See merge request !275

Code cleanup

See merge request !277

Set the applyToAllLineItems flag if all the lineitems on the form were specified in the discount code

For event multiple participants don't require payment details if all priceset amounts are zero (ie. 100% discount)

Issue #265: Order by Price Set ID

Add attribute discount-applied=1 to discountcode textfield when discount is applied and valid

Make description field required on the form

Remove return from void functions

Use icon helper in templates

Remove unused internal function

Ensure postprocess is called only once

Correct image paths

Increment info.xml

We'll drop a release once https://github.com/civicrm/org.civicrm.module.cividiscount/pull/255
is sorted

Fix save to stop overwriting calculated value

This matters when total_amount is a submitted value

Opps the last attempt to remove the 4.6 code was too broad - remove & redo

This reverts commit 410adf6f.

Remove support for pre 4.6.4