Removed some redundant and/or unnecessary build settings
Declare getPlugin function public.  Link against libboost_system (which is required by Boost.Thread).
Merging upstream changes
Moved MWorksCore includes to prefix header.  Pass -headerpad_max_install_names option to linker.  Minor tweaks.
Merge pull request #3 from dicarlolab-mworks/master

0.5 release cleanup