Get Twig's .test syntax running
Remove some of the attempted automatic process control

This isn't working right for multiple tests yet. Easier to switch back to
manually running "node test/dnode.js" for the time being.
Add test case for schmittjoh/twig.js#67
Tidy up Twig *.test support

This makes the PHPUnit suite continue to work even if executed on a machine
without the dnode server running. The tests are marked as incomplete instead of
simply dropping the exception on the floor and failing the suite.
Port array.test from Twig's test suite

This has surfaced a minor incompatibility. I had to change line 56 of this test
from `FOO,BAR,` to `FOO,BAR,false`. Twig prints boolean false values as an empty
string, and Twig.js prints them as the word "false".
Port array_call.test from Twig
Copy Twig's directory structure
Port the join filter test from Twig
Port the nl2br filter test from Twig

This has exposed a minor incompatibility. Twig puts a newline after the <br />
tags that this filter generates, whereas Twig.js doesn't. I've had to edit the
test to reflect this discrepancy.
Port the range function test from Twig

This exposes another minor incompatibility. Twig's range function supports a
step parameter which doesn't exist in Twig.js. I've edited the test to remove
this.
Make the test suite start and stop the dnode server automatically
Automate the entire test suite under "make test"