json-cpp Code

- fixed build issue on AIX. Build both shared and static library is now only activated on Linux. Building static library on other platforms.

- fixed build issue with mingw (bug 2834969)

Fixed comment after value in object value signaled by Frederic Surleau.

- added Features class that describes allowed extension for Reader, to allow for strict configuration
- added tests from json.org jsonchecker and modified jsontestrunner to use strict parsing mode when executing them

- fixed SCons build on Windows: only build static library (support static/dynamic at the same time requires significant changes)
- renamed SCons glob tool to globtool to avoid clash with python glob module. This prevented running the tests.
- check target now works with SCons 1.x

Fixing string index issue when checking for control characters

Fixed default constructor initialization.

Fixed bug introduced by utf-8 patch with fix provided by Henry Ludemann. All unit tests are now passing.

Added patch for mingw from Sebastien Vincent

Implementing support for reading and writing Unicode escape sequences.