Add acceptance tests

Basic Framework for working with Selenium with PHPUnit and Firefox.
Future acceptance tests just need to extend Base.php and implement
various flows that we wish to test.

tests/acceptance.xml

@@ -0,0 +1,13 @@
+<phpunit stopOnError="true" stopOnFailure="true" colors="true">
+    <testsuites>
+        <testsuite name="Kanboard">
+            <directory>acceptance</directory>
+        </testsuite>
+    </testsuites>
+    <php>
+        <const name="SELENIUM_HOST" value="localhost" />
+        <const name="SELENIUM_PORT" value="4444" />
+        <const name="DEFAULT_BROWSER" value="firefox" />
+        <const name="KANBOARD_APP_URL" value="http://localhost:8001" />
+    </php>
+</phpunit>