Add irange.pxd with minimal Cython interface for dynd::irange.

Author: insertinterestingnamehere

dynd/cpp/irange.pxd

@@ -0,0 +1,12 @@
+from ..config cimport translate_exception
+
+cdef extern from "dynd/irange.hpp" namespace "dynd" nogil:
+    cppclass irange:
+        irange()
+        # Use size_t for this interface since Cython doesn't know
+        # how to directly convert integer literals in the source
+        # to intptr_t. It can do that with size_t and on the overwhelming
+        # majority of platforms that's exactly the same thing.
+        irange(size_t)
+        irange(size_t, size_t)
+        irange(size_t, size_t, size_t)