BigInteger: guard against self-assignment

Related-to: #404.
Suggested-by: @cosinekitty

doc: 自定义流应当使用 ParseStream 而不是 Parse

added missing fields of CMakeList.txt

this fixed cmake error for me

Implement = operator for BigInteger

There's a copy constructor, but no '=' operator implemented. This is dangerous.

Fix include location

@PlatformIO Library Registry manifest file

* This library in Web Registry: http://platformio.org/#!/lib/show/438/RapidJSON
* Specification: [PlatformIO Library Manager](http://docs.platformio.org/en/latest/librarymanager/index.html)
* Integration: [IDE Integration](http://docs.platformio.org/en/latest/ide.html)

Fix the error when compiled using vs2013

The error message for the original codes is: unary minus operator applied to unsigned type, result still unsigned. Added static casting to eliminate this message.

Warning cleanup on osx10.10/clang, enable -Werror

This reverts commit 5be9b6e5.

Clarify problematic JSON license (#377)

Prohibit C++11 move from Document to Value

Add to FAQ: How to insert a document node into another document?

As reported in #387, silently moving a `GenericDocument` to a
`GenericValue` can lead to object slicing and premature deletion of
the owning allocator of the (surviving) `GenericValue`.

To reduce this risk, prohibit move construction of a `GenericValue`
from a `GenericDocument`.

add GenericDocument<>::Swap with std::swap() support

This avoids the dependency on the <algorithm> header, as suggested by
@miloyip in #376.

Make it usable with old VC8 (VS2005)

Add #pragma intrinsic(_umul128) for MSVS 2005

Add #pragma intrinsic(_umul128) for MSVS 2005

Add GenericDocument ctor overload to specify JSON type.

See #368.

Update FAQ 8 with shorter version of clean-and-minimize idiom

Credits to @pah who suggested it in comment to #368.