json-cpp Code

- added Int/UInt typedef in Json namespace. Modified Value::Int and Value::UInt to be typedef on those. Modified code to use Json::Int instead of Value::Int.
- added Value constructor taking begin/end pointer to initialize the Value with a non-zero terminated string.

- added a large test that cause(d?) crash with experimental JSON_VALUE_USE_INTERNAL_MAP

renamed jsontestrunner.py to pyjsontestrunner.py to avoid confusion

- fixed failing test

Integrated part of Patch #2839016, fixing default iterator initialization when using internal map.

Added another failing unicode test case

Fixed compilation with Sun Studio 12 (avoid usage of std::distance)

Fixed iteration bug over null values.

Added instruction to run unit tests manually.

Moved jsontestrunner data from test/ to test/data.