Donation Receipts 1.8 Beta 3

New features / enhancements

• [#79] Create donation_receipt_tokens hook - by @bjendres, @rubofvil, @sluc23
• [#51] Select year relevant for ID generator - by @bjendres, @sluc23, @rubofvil
• [#83] Provide a setting for selecting which contribution fields to lock for editing - by @jensschuppe
• [#86] "is receipted" column should not be filled using JavaScript - by @jensschuppe

Bugfixes

• [#82] Fix Syntax Error in SQL Query - by @marcelklehr