Upgrade the rapidjson library to version 1.1.0. This version
contains fixes that remove compiler warnings on newer versions
of clang, plus several other enhancements and bugfixes.

We previously had a modification in the library, where we could
choose to handle "-0" as a double value in order to preserve
the signedness. This was mainly used by GIS code. Now, we send a
flag to the JSON parser telling us whether to parse ALL numbers
as double or not. This effectively uses the RawNumber callback in
rapidjson instead of the individual Int64/Double/Int... callbacks.
We now use this functionality instead of modifying the library,
so that all custom modifications can be removed.

Change-Id: I784ad30bca474ba1872ebb4e2d5867c4e11b9dd2