Added full support for the LTDL_LIBRARY_PATH with MSVC plugins. Using the
semicolon as item separator similar to ltdl. TODO: make the MSVC plugin
handling work with the other win32 ports.
Minor cleanups in the plugin code.


git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@11938 6c8e4198-a580-4521-a02f-c9ae86df1db9