Fixes bug in indexOf when needle not found.

Also fixes same bug in lastIndexOf.
Enlarges tests for string methods.

Now includes tests for indexOf.  Also adds collectionsPrelude
to GRACE_MODULES so that node.js test harness can find them.
Adjust JS test build to work without installation

The build process for the JavaScript tests relied on the system being
installed in order to resolve paths appropriately. Now the tests can be
run locally.