Parse JSON number to double in full-precision with custom strtod. Fix #120

Add move constructor and prohibit copy constructor and assignment
operator.

https://github.com/miloyip/rapidjson/issues/120#issuecomment-54428797

GenericValue: improve copying performance

The GenericValue "copy" constructor (with Allocator) uses a temporary
GenericDocument object to perform the deep copying with the provided
allocator.  This leads to the temporary allocation of the `Stack`
memory, even in case of shallow values (numbers, etc.).

This patch improves the performance of this operation by only resorting
the the SAX Handler implementation in case of Array or Object values.

Compile all examples with the Dinkum C++ of QNX 6.6

QCC -Wall -Wextra -Vgcc_ntoarmv7le -I../include <example>

GenericDocument: explicitly prohibit copying

See #201.

Minor (documentation) cleanups

Avoids implicit conversion from an `OutputStream` (or an allocator pointer)
to a `Writer` instance.

Use absolute path for the link to examples

Conflicts:
	include/rapidjson/internal/dtoa.h
	test/unittest/readertest.cpp

Allow customization of RapidJSON namespace

Document traits of types using <type_traits> and static_assert in tests

The tests state the current traits of types Document, Value and
StringBuffer. There are slight differences between them. It seems like a
good idea to extend this approach across more types, and to review the
expected traits across the board.

MemoryPoolAllocator, Stack: lazily allocate Allocators 

DocumentMove tests: compiler error due to -Wsign-compare

Add unit tests for StringBuffer

On GCC 4.9, the documenttest.cpp fails to compile in C++11 mode,
as the MoveConstructor/Assignment tests contain left-over
comparisons between signed and unsigned expressions.