Adjust CMakeLists.txt and .def: add _d postfix onto jansson_d.lib/dll

Had to remove the "LIBRARY" line from jansson.def, which was optional,
and was overriding CMake's desire for a specific name.
Merge pull request #120 from paulharris/mine_pre_2.5

Adjust CMakeLists.txt and .def: add _d postfix onto jansson_d.lib/dll