json-cpp Code

Comment reading/write improvements

This patch fixes some aspects of reading and writing comments:
- Multiple C++-style comments before a Json value had extra newlines appended to them. This patch removes the addition of those newlines.
- Comments written before Json values in the StyledWriter were not indented to match the indentation level of the value. This patch adds indentation to comments.
- Fixed inconsistency in newlines following C- and C++-style comments being saved as part of the comment. All newlines at the end of a comment are now removed.
- Added an additional test of comments.

https://sourceforge.net/p/jsoncpp/patches/25/

JSON_ASSERT -> JSON_ASSERT_MESSAGE

This way, assertions can produce exceptions.
https://sourceforge.net/p/jsoncpp/bugs/67/

Added missing includes for std::istream.

Thanks to Quentin Fiard for the report.

Fixed broken build on VS 2012

Fixed some snprintf-related build breakages in Visual Studio.

Updated two calls to sprintf that I missed in r269.

Replaced the complex implementation of valueToString(double).

The previous one was confusing and prone to buffer overflows, and didn't
work correctly with 16-decimal-digit numbers. The new one simply uses
snprintf with a standard format string.

The major change is that we don't always print a decimal point now.
Fortunately, JSON doesn't distinguish between integers and reals.

Added more floating point tests.

The first demonstrates a bug that I will soon fix.

Added further floating point tests.

Switched away from sprintf, which is prone to buffer overflows.

Most reasonable platforms have this function. If you're here because
this broke the build for you, consider adding an ifdef for your platform
and using sprintf there (but not on other platforms).