X .nxdtest: Initial draft

To run wendelin.core tests under Nexedi testing infrastructure.

.nxdtest

+# setup to run tests on Nexedi testing infrastructure.
+# https://stack.nexedi.com/test_status
+
+# test matrix: {fs,zeo,neo}-{!wcfs,wcfs}
+for stor in ['fs', 'zeo', 'neo']:
+    for wcfs in [False, True]:
+        name = '%s-%swcfs' % (stor, '' if wcfs else '!')
+        envadj = {
+            'WENDELIN_CORE_TEST_DB': '<%s>' % stor,
+            'WENDELIN_CORE_VIRTMEM': 'r:wcfs+w:uvmm' if wcfs else 'rw:uvmm',
+        }
+
+        # TODO summaryf=?
+        TestCase(name, ['make', 'test'], envadj=envadj)