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/Stat.py

@@ -0,0 +1,39 @@
+# automatically generated, do not modify
+
+# namespace: Example
+
+import flatbuffers
+
+class Stat(object):
+    __slots__ = ['_tab']
+
+    # Stat
+    def Init(self, buf, pos):
+        self._tab = flatbuffers.table.Table(buf, pos)
+
+    # Stat
+    def Id(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(4))
+        if o != 0:
+            return self._tab.String(o + self._tab.Pos)
+        return ""
+
+    # Stat
+    def Val(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(6))
+        if o != 0:
+            return self._tab.Get(flatbuffers.number_types.Int64Flags, o + self._tab.Pos)
+        return 0
+
+    # Stat
+    def Count(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(8))
+        if o != 0:
+            return self._tab.Get(flatbuffers.number_types.Uint16Flags, o + self._tab.Pos)
+        return 0
+
+def StatStart(builder): builder.StartObject(3)
+def StatAddId(builder, id): builder.PrependUOffsetTRelativeSlot(0, flatbuffers.number_types.UOffsetTFlags.py_type(id), 0)
+def StatAddVal(builder, val): builder.PrependInt64Slot(1, val, 0)
+def StatAddCount(builder, count): builder.PrependUint16Slot(2, count, 0)
+def StatEnd(builder): return builder.EndObject()