Merge pull request microsoft#8 from Microsoft/nocopy

Use a single rapidjson::Document and allocator for the entire result set

Fix UNIX compile options

I removed the `graphqlpeg` library as a separate target, but I still had compile options set for it on UNIX.

Merge pull request microsoft#3 from Microsoft/rapidjson

Port JSON parsing/generation from cpprestsdk to RapidJSON

Merge pull request microsoft#2 from Microsoft/pegtl

Replace the GraphQL parser with a PEGTL implementation

Make copying other Windows DLLs to the install directory optional

Fix CMake/Ninja build in VS 2017