Collapse the five 0/1-based index flags into one option.

tests/generators/unittest_php.js

@@ -172,7 +172,7 @@ Blockly.PHP['unittest_adjustindex'] = function(block) {
   var index = Blockly.PHP.valueToCode(block, 'INDEX',
       Blockly.PHP.ORDER_ADDITION) || '0';
   // Adjust index if using one-based indexing.
-  if (Blockly.PHP.ONE_BASED_INDEXING) {
+  if (block.workspace.options.oneBasedIndex) {
     if (Blockly.isNumber(index)) {
       // If the index is a naked number, adjust it right now.
       return [parseFloat(index) + 1, Blockly.PHP.ORDER_ATOMIC];