add flatbuffers

commit 6da1cf79d90eb242e7da5318241d42279a3df3ba
Author: Max Burke <max@urbanlogiq.com>
Date:   Sun Jan 19 14:47:28 2020 -0800

    [rust] Add use declarations to Rust-generated bindings for imported FB definitions (#5645)

    * Bugfix for Rust generation of union fields named with language keywords

flatbuffers/tests/namespace_test/NamespaceA/SecondTableInA.py

@@ -0,0 +1,75 @@
+# automatically generated by the FlatBuffers compiler, do not modify
+
+# namespace: NamespaceA
+
+import flatbuffers
+from flatbuffers.compat import import_numpy
+np = import_numpy()
+
+class SecondTableInA(object):
+    __slots__ = ['_tab']
+
+    @classmethod
+    def GetRootAsSecondTableInA(cls, buf, offset):
+        n = flatbuffers.encode.Get(flatbuffers.packer.uoffset, buf, offset)
+        x = SecondTableInA()
+        x.Init(buf, n + offset)
+        return x
+
+    # SecondTableInA
+    def Init(self, buf, pos):
+        self._tab = flatbuffers.table.Table(buf, pos)
+
+    # SecondTableInA
+    def ReferToC(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(4))
+        if o != 0:
+            x = self._tab.Indirect(o + self._tab.Pos)
+            obj = TableInC()
+            obj.Init(self._tab.Bytes, x)
+            return obj
+        return None
+
+def SecondTableInAStart(builder): builder.StartObject(1)
+def SecondTableInAAddReferToC(builder, referToC): builder.PrependUOffsetTRelativeSlot(0, flatbuffers.number_types.UOffsetTFlags.py_type(referToC), 0)
+def SecondTableInAEnd(builder): return builder.EndObject()
+
+try:
+    from typing import Optional
+except:
+    pass
+
+class SecondTableInAT(object):
+
+    # SecondTableInAT
+    def __init__(self):
+        self.referToC = None  # type: Optional[TableInCT]
+
+    @classmethod
+    def InitFromBuf(cls, buf, pos):
+        secondTableInA = SecondTableInA()
+        secondTableInA.Init(buf, pos)
+        return cls.InitFromObj(secondTableInA)
+
+    @classmethod
+    def InitFromObj(cls, secondTableInA):
+        x = SecondTableInAT()
+        x._UnPack(secondTableInA)
+        return x
+
+    # SecondTableInAT
+    def _UnPack(self, secondTableInA):
+        if secondTableInA is None:
+            return
+        if secondTableInA.ReferToC() is not None:
+            self.referToC = TableInCT.InitFromObj(secondTableInA.ReferToC())
+
+    # SecondTableInAT
+    def Pack(self, builder):
+        if self.referToC is not None:
+            referToC = self.referToC.Pack(builder)
+        SecondTableInAStart(builder)
+        if self.referToC is not None:
+            SecondTableInAAddReferToC(builder, referToC)
+        secondTableInA = SecondTableInAEnd(builder)
+        return secondTableInA