Update rapidjson to latest code from github

Author: tristanpenman

CMakeLists.txt

@@ -77,7 +77,7 @@ include_directories(include SYSTEM
     thirdparty/gtest-1.11.0/include
     thirdparty/json11-ec4e452
     thirdparty/jsoncpp-1.9.4/include
-    thirdparty/rapidjson-1.1.0/include
+    thirdparty/rapidjson-48fbd8c/include
     thirdparty/picojson-1.3.0
     thirdparty/nlohmann-json-3.1.2
     )

README.md

@@ -209,12 +209,12 @@ Valijson supports JSON documents loaded using various JSON parser libraries. It
  - [json11 (commit afcc8d0)](https://github.com/dropbox/json11/tree/afcc8d0d82b1ce2df587a7a0637d05ba493bf5e6)
  - [jsoncpp 1.9.4](https://github.com/open-source-parsers/jsoncpp/archive/1.9.4.tar.gz)
  - [nlohmann/json 1.1.0](https://github.com/nlohmann/json/archive/v1.1.0.tar.gz)
- - [rapidjson 1.1.0](https://github.com/miloyip/rapidjson/releases/tag/v1.1.0)
+ - [rapidjson (commit 48fbd8c)](https://github.com/Tencent/rapidjson/tree/48fbd8cd202ca54031fe799db2ad44ffa8e77c13)
  - [PicoJSON 1.3.0](https://github.com/kazuho/picojson/archive/v1.3.0.tar.gz)
  - [Poco JSON 1.7.8](https://pocoproject.org/docs/Poco.JSON.html)
  - [Qt 5.8](http://doc.qt.io/qt-5/json.html)
 
-Other versions of these libraries may work, but have not been tested. In particular, versions of JsonCpp going back to 0.5.0 should also work correctly.
+Other versions of these libraries may work, but have not been tested. In particular, versions of jsoncpp going back to 0.5.0 should also work correctly.
 
 ## Package Managers ##
 
@@ -232,7 +232,7 @@ The exceptions to this are boost, Poco and Qt5, which due to their size must be
 
 When using PicoJSON, it may be necessary to include the `picojson.h` before other headers to ensure that the appropriate macros have been enabled.
 
-When building Valijson using CMake on Mac OS X, with Qt 5 installed via Homebrew, you may need to set `CMAKE_PREFIX_PATH` so that CMake can find your Qt installation, e.g:
+When building Valijson using CMake on macOS, with Qt 5 installed via Homebrew, you may need to set `CMAKE_PREFIX_PATH` so that CMake can find your Qt installation, e.g:
 ```bash
     mkdir build
     cd build