Changes for generation of Invoice
VAT-388 Added new files for generation of invoice.
Removed same code from postprocess() function which is required for Invoice generation and PDF generation
Changed hard coded URL for image and changed variable  to .
VAT-388 some minor changes for code
VAT-88 Removed hardcode query during upgrade.
VAT-365 Tax label changes and code optimization.
VAT-434 Batching contributions for Export
VAT-388 Added message templates of contribution invoice receipt for handle upgrade
Removing line used to get configuration array
Some minor changes for Invoice.php
Revert "Removing line used to get configuration array"

This reverts commit eb12c6d02725226412951ae9c64366e3367a26ee.
Added ts() for VAT (exempt).
Merge pull request #7 from rohankatkar/VAT_Issue_388

VAT-388  Added action for Print or Email Invoice. Created template for invoice.
Merge pull request #11 from dpradeep/VAT-88-New

VAT-88 Removed hardcode query during upgrade.
Merge pull request #12 from dpradeep/VAT-365-New

VAT-365 Tax label changes and code optimization.
Merge pull request #13 from dpradeep/VAT-434

VAT-434 Batching contributions for Export
VAT-414 The system public pages should be updated to show the VAT/Tax breakdown for all line items on each contribution record and in a price set.
VAT-415 The default receipts that the system sends out should be updated to show the VAT/Tax breakdown.
VAT-416 Added display option for button on display preferences page. Populate the download option on click of Print Invoice button.