added Preferences (zoom, MenuMode)

src/main/java/com/ardublock/Main.java

src/main/java/com/ardublock/core/Context.java

src/main/java/com/ardublock/ui/OpenblocksFrame.java

src/main/resources/com/ardublock/block/ardublock.properties

...ain/resources/com/ardublock/block/ardublock_de.properties

.../resources/com/ardublock/block/ardublock_en_GB.properties