fixes #411

Fixed a bug that caused Oracle to be stuck in an infinite loop if the default path checkbox was checked but failed to write.

If a path to cards.xml is set, Oracle will update that cards.xml.
If Oracle is run before a path to cards.xml is set, if default is checked, cards.xml will be saved on the AppData path. Furthermore, this path will be set as the cards.xml path for both Oracle and Cockatrice.
If Oracle is run before a path to cards.xml is set, if default is NOT checked, cards.xml will be saved at the selected path and this path will be set as the cards.xml path for both Oracle and Cockatrice.
If a path to cards.xml is set, if default is NOT checked, cards.xml will be saved at the selected path but this path will NOT be set as the cards.xml path for either Oracle or Cockatrice. This allows people who already have a cards.xml (which may be customized), to still obtain clean copies of cards.xml through Oracle without overwriting their own

Ref #127

You won’t have to copy manually all the dlls in the release directory
anymore

Without this change, make install and make package would require “sudo”
under osx

Without this change, make install and make package would require “sudo”
under osx

It will be saved only if:
* it’s different than the default (the user used a custom url);
* the download actually worked

By default oracle saves cards.xml to the correct path, where cockatrice
will be able to pick it up;
if oracle is not able to determine the path or the user unchecks the
option, oracle will ask for a save path