Make get_add_path and get_edit_path more reusable

Issue Summary

I'm writing a patch for uc_cck_pane to provide content_profile integration. I noticed the two functions content_profile_get_add_path() and content_profile_get_edit_path() so figured they must be useful, but then realised that I need to include content_profile.theme.inc. Is there a reason those functions are in the include file and not the main module file? It is very tempting to not bother using the functions given that I have to load the include file myself.