Fix download of bukkit server jars.
Merge branch 'master' of https://github.com/Thue/rfwadmin
Add default values to properties, avoiding error message when property doesn't exist in server.properties.

Fixes issue #22.
Rm now obsolete warning text about bukkit server downloads.
A simple interface for uploading bukkit plugins.

Closes issue #24.
Merge remote-tracking branch 'thue/master'