o.c.swt.widgets: Allow resources from web links with spaces

BOY Images (and *.opi files in general) didn't load if the URL contained
spaces. Need "%20" for that, but at the same time must keep the space
when loading the file locally from file system.
attempt to catch more than spaces
shouldn't have removed the replace space with %20
Merge pull request #402 from ControlSystemStudio/bug401

o.c.swt.widgets: Allow resources from web links with spaces