Update dhtnode.c

Added a function that calculates difference |a - b| between keys a and b
Update dhtnode.c
Update dhtnode.c

Find closer key method implemented
Create test_key_difference.c
Update dhtpacket.c

Minor update in destroy_packet
Update dhtnode.c
Update dhtnode.c
Update dhtpacket.c
Update dhtpacket.h
Minor update
Minor update
Update dhtnode.c

B2 should now work. B3 packet sending unimplemented.
Update dhtnode.c

Should work now... but only with the dummy utilities (test_data_x etc.)
Fix update for dhtnode.c
Update dhtnode.c

Now all the functionality should be working... only some manager dependencies need some tweaking
GUI for DHT Client with, main window modal dialogue and basic functionality for included buttons
Replaced NetBeans generated code. Scrollpane scrollbar missing.
Custom icon button class
Make command for compiling & running GUI
Improve GUI make command