Use the new CHEMKIT_OS_* defines in the PluginManager class
Use the new CHEMKIT_OS_* defines in the PluginManager class

This changes the PluginManager class to use the new CHEMKIT_OS_*
defines instead of the Q_OS_* defines.

kylelutz/chemkit,kylelutz/chemkit,kylelutz/chemkit,kylelutz/chemkit