Add capnp.pxd for public declarations of cython classes

capnp/includes/types.pxd

@@ -0,0 +1,19 @@
+from cpython.ref cimport PyObject, Py_INCREF, Py_DECREF
+from cpython.exc cimport PyErr_Clear
+from libc.stdint cimport *
+ctypedef unsigned int uint
+ctypedef uint8_t byte
+ctypedef uint8_t UInt8
+ctypedef uint16_t UInt16
+ctypedef uint32_t UInt32
+ctypedef uint64_t UInt64
+ctypedef int8_t Int8
+ctypedef int16_t Int16
+ctypedef int32_t Int32
+ctypedef int64_t Int64
+
+ctypedef char * Object
+ctypedef bint Bool
+ctypedef float Float32
+ctypedef double Float64
+from libcpp cimport bool as cbool