load.video fails when filename includes whitespace

[rupertoverall]

I have discovered that filenames including whitespace (legal names on the OS X platform) confound load.video which fails with the error:

Error in tryCatchList(expr, classes, parentenv, handlers) : 
  No output was generated

Renaming offending directories in the path to avoid whitespace is a fix, but support for these should be easy to add.