refactored python startup files for ost and dng

there are now three startup files; ost_startup.py (former init_cl.py) initializes non-gui ost; dng_startup (former init.py) initializes dng; and gosty_startup initializes gosty (some issues remain what to put into dng_startup as opposed to gosty_startup). also, files are now properly placed into site-packages/ost (on osx and linux)