gvle: fix the configuration of oov

The data used for configuring the oov were remvoved when launching from gvle.
API of vpz has been extended with a function that modifies only the location
of an Output (Closes #99).
gvle: fix the rename function of the FileTreeView

The wrong variable was used as old path in the call of Package::rename.
(Closes #98)
gvle: fix file copy into the FileTreeView

The line that copies files was missing into onPaste function
(Closes #100)
gvle: fix the unhandled copies

Copy/paste feature only works if the target is a file with a file extension.
In case the target did not follow these requirements a std exception was
thrown. Instead we now do nothing. (Closes #101)