Port FlatBuffers to Python.

Implement code generation and self-contained runtime library for Python.

The test suite verifies:
  - Correctness of generated Python code by comparing output to that of
    the other language ports.
  - The exact bytes in the Builder buffer during many scenarios.
  - Vtable deduplication correctness.
  - Edge cases for table construction, via a fuzzer derived from the Go
    implementation.
  - All code is simultaneously valid in Python 2.6, 2.7, and 3.4.

The test suite includes benchmarks for:
  - Building 'gold' data.
  - Parsing 'gold' data.
  - Deduplicating vtables.

All tests pass on this author's system for the following Python
implementations:
  - CPython 2.6.7
  - CPython 2.7.8
  - CPython 3.4.2
  - PyPy 2.5.0 (CPython 2.7.8 compatible)

tests/MyGame/Example/Vec3.py

@@ -0,0 +1,44 @@
+# automatically generated, do not modify
+
+# namespace: Example
+
+import flatbuffers
+
+class Vec3(object):
+    __slots__ = ['_tab']
+
+    # Vec3
+    def Init(self, buf, pos):
+        self._tab = flatbuffers.table.Table(buf, pos)
+
+    # Vec3
+    def X(self): return self._tab.Get(flatbuffers.number_types.Float32Flags, self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(0))
+    # Vec3
+    def Y(self): return self._tab.Get(flatbuffers.number_types.Float32Flags, self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(4))
+    # Vec3
+    def Z(self): return self._tab.Get(flatbuffers.number_types.Float32Flags, self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(8))
+    # Vec3
+    def Test1(self): return self._tab.Get(flatbuffers.number_types.Float64Flags, self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(16))
+    # Vec3
+    def Test2(self): return self._tab.Get(flatbuffers.number_types.Int8Flags, self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(24))
+    # Vec3
+    def Test3(self, obj):
+        obj.Init(self._tab.Bytes, self._tab.Pos + 26)
+        return obj
+
+
+def CreateVec3(builder, x, y, z, test1, test2, Test_a, Test_b):
+    builder.Prep(16, 32)
+    builder.Pad(2)
+    builder.Prep(2, 4)
+    builder.Pad(1)
+    builder.PrependInt8(Test_b)
+    builder.PrependInt16(Test_a)
+    builder.Pad(1)
+    builder.PrependInt8(test2)
+    builder.PrependFloat64(test1)
+    builder.Pad(4)
+    builder.PrependFloat32(z)
+    builder.PrependFloat32(y)
+    builder.PrependFloat32(x)
+    return builder.Offset()