Attached is a patch containing a few obvious fixes for warnings in the
plugins, mostly adding consts, gpointer casts and unsigned int loop
The only one that is likely to have been bad (tm) is in treebrowser.c
it g_freed a static string. Setting the string const found that.
treebrowser.c still has warnings about two unused variables, since in
each case some work is done to set them, the treebrowser maintainer
should look and see if they are meant to be used somewhere, or remove
them and the setting code.