Fix for #218 - Check empty namespace in general generator

If you have a schema with no namespace, the resulting C#/Java won't have
an erroneous empty namespace keyword.

Normal behavior is to not output fields that happen to have
the default value, since those will be reproduced anyway
when turned into a FlatBuffer binary. This however can be problematic
when using JSON to interop with other system since they might not
know this default value. This flatc option (and also flag
to GenerateText) will force those fields to be output anyway.

Tested: on Linux.

Change-Id: Ib2b7aa8a5641cf73fa0d6f2000db7fdd1aabab66
Tested: on Linux.

Change-Id: I290c33c475f7b019ab0d3c571245d27351d22fa1
Tested: on Linux.

Change-Id: Iea5fab66047ac0a5057a743dbb1fdb27c063188c
Tested: on Linux.

Change-Id: Id268e35de207c25c809a09071b81eea873c9123e
Tested: on Linux.

Add include for cstdlib for std::bsearch definition

Go: CreateString now needs zero allocs.

Big speed boost for the typical use case of building with strings.

Fixed endianness Vector's begin() and end()

Use std::bsearch in LookupByKey for binary search

Update Python docs and package description

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)

Go speed improvements

Issue #188

Added a default constructor for Java's FlatBufferBuilder.

Change-Id: Ib561430b235eddf4bfe20f68409e1dfdb359ef2b
Tested: on Linux.

Default's size of 1024b like in cpp. Fixes #190.

When accessing the array directly of a byte buffer, need to offset
by ``arrayOffset``

When accessing a union field, we should return the same object type
as was given to the method, i.e. the parameter should have a generic
type for any Table-derived type. This way, we do not need to make
superfluous casts (which also reduce type safety) like

var myUnionType = (MyUnionType)buff.GetUnionField(new MyUnionType());

when we can do just
var myUnionType = buff.GetUnionField(new MyUnionType());

Change-Id: Idac1b638e46cc50b1f2dc19f10741481202b1515