Older GCC versions fail compiling RapidJSON due to a warning

include/rapidjson/reader.h:578: error: suggest a space before ';' or explicit braces around empty body in 'while' statement
: warnings being treated as errors

fix #749

Add StringBuffer::GetLength()

Fix #744

Move constructor support for Writer

This also requires turning off the c++98 compatibility checks when building
with clang.

Refactor regex

Remove mutable which causes reentrant issue

Add preconditions in writer and string functions

Fix typo in doc

fix wrong length in remote schema

Change-Id: Ia96ddf5746f1c18968e9e086f17fe4a24b8480d7

Remove non-compiling assignment operator

Version 1.1.0

Change version numbers
Fixed some document linkage
Fix #648

Fix builds on x32 platform.

From the Debian wiki: https://wiki.debian.org/X32Port

X32 is an ABI for amd64/x86_64 CPUs using 32-bit integers, longs
and pointers. The idea is to combine the smaller memory and cache
footprint from 32-bit data types with the larger register set of
x86_64. The 64-bit registers can make computation more efficient,
and with 8 additional registers available, there is less pressure
compared to i386/i686.

rapidjson makes an incorrect assumption in a check for 64 bit
platforms, and uses __LP64__ exclusively. This fix adds an
additional check for __x86_64__ && __ILP32__ defines, as a very
conservative fix. However, the usage of __LP64__ would be a problem
for other "mixed" applications like ARM ILP32, so a better detection
scheme might be needed in the future.

Add std::string overload to PrettyWriter::Key() when RAPIDJSON_HAS_STDSTRING is #defined

Only String() has the std::string overload currently.

Handle malloc() fail in PoolAllocator

Fix #682

optimize FindMember  when use std::string

Add Flush() for all value types

Fixes #684

also use internal::StrLen to get the string lengtht,
when it call FindMember(StringRef(name)).
Now use GenericValue construct it, then can use the std::string.size.
now it will be faster.

fix rapidjson::value::Get<std::string>() may returns wrong data