propagate the parent app's OSUserAppDir (i.e. ~/.secondlife/) all the way down to plugins, if they need persistant user data/settings (like the webkit plugin needs a place to put its cache).
svn merge -r 129913:131718 svn+ssh://svn.lindenlab.com/svn/linden/branches/pluginapi/pluginapi_05
Some branch shenannigans in the pluginapi_05 branch caused this to become a two-part merge.
Tofu Linden