added example for sorting keys

[sekyHC]

We needed a way to sort keys and lost a day to find out how to do it. That is why we are contributing back to this awesome library with an example

[coveralls]

Coverage remained the same at 99.921% when pulling d018846 on HomeControlAS:sort_by_name_example into 30d92a6 on Tencent:master.

[miloyip]

const Value& is sufficient

[sekyHC]

good info 👍

[miloyip]

I think it may be better to have this example without using std::string

[sekyHC]

removed std::string

[miloyip]

It still cannot compile. Due to not supporting pre-C++11?

[sekyHC]

I am compiling it as per instructions here: https://github.com/Tencent/rapidjson#installation

output:

 ~/s/rapidjson   sort_by_name_example  build  make                                                                                               10:30
[  2%] Built target simplepullreader
[  5%] Built target tutorial
[  7%] Built target jsonx
[ 10%] Built target pretty
Scanning dependencies of target sortkeys
[ 11%] Building CXX object example/CMakeFiles/sortkeys.dir/sortkeys/sortkeys.cpp.o
[ 12%] Linking CXX executable ../bin/sortkeys
[ 12%] Built target sortkeys
[ 15%] Built target condense
[ 17%] Built target simpledom
[ 20%] Built target messagereader
[ 23%] Built target simplewriter
[ 25%] Built target filterkeydom
[ 28%] Built target filterkey
[ 30%] Built target lookaheadparser
[ 33%] Built target capitalize
[ 35%] Built target parsebyparts
[ 38%] Built target prettyauto
[ 41%] Built target schemavalidator
[ 43%] Built target simplereader
[ 46%] Built target serialize
[ 46%] Built target examples
[ 50%] Built target archivertest
[ 52%] Built target namespacetest
[ 55%] Built target gtest
[ 57%] Built target gtest_main
[ 92%] Built target unittest
[100%] Built target perftest
[100%] Built target tests