Log converting progress

[dfredell]

Log the progress in percent of unpacking the input db to the output tar.

When I first ran this program it was sitting there without giving any indication to the user that it was working. This feature will let the user know the app is working and the progress of the 'unpack' task.

[nelenkov]

Thanks for this. Looks OK, but could you clean up a few things:

• remove package commit (import java.io.*)
• try not to change unrelated code (i.e. long read = -1)
• make double float conversion explicit (var + .0 i messy)

[nelenkov]

thanks