Added features that allow the reader to accept common non-standard JSON.

This is a version of patch #17, from Clay Wood:

    http://sourceforge.net/p/jsoncpp/patches/17/

git-svn-id: svn://svn.code.sf.net/p/jsoncpp/code/trunk@280 1f120ed1-78a5-a849-adca-83f0a9e25bb6
Added structured error reporting to Reader.

This allows applications for interactively viewing or editing JSON to do
a better job of highlighting errors. Also added offset accessors to
Value, offering the same sort of functionality even for non-errors.

Thanks to Zach Clifford (zacharyc@google.com) for the patch.

git-svn-id: svn://svn.code.sf.net/p/jsoncpp/code/trunk@281 1f120ed1-78a5-a849-adca-83f0a9e25bb6
Fixed a test that causes a crash when exceptions are disabled.

While I was at it, corrected whitespace too.

git-svn-id: svn://svn.code.sf.net/p/jsoncpp/code/trunk@282 1f120ed1-78a5-a849-adca-83f0a9e25bb6