Third-party AddIns installed in SharpDevelop/AddIns are now visible in the AddInManager, only AddIns with 'addInManagerHidden="preinstalled"' stay hidden.
git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/branches/3.0@3806 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61