6top protocol implementation

Define commands, return codes, states and 6top variables

Added 6P enqueue ADD function.

Adjusted cell reservation request to enable 6P messaging. Added settings variable 6P messaging.

Implemented missing message types, receive_ADD function, enqueue_RESPONSE function.

Added 6P receive_RESPONSE functionality. Added code field to packet.

Added receive_response_ack functionality.

Minor changes to fix code.

Update types for 6top

Send DATA packets are only send when dedicated TX cells are available

Editing readme and header in Mote.py with new authors Glenn and Esteban

Several Bug Fixes

Edit Reservation Request with states, blocked cells and seqNum

Editing enqueue ADD request

Modifying Receive ADD Request with states, RC, seqNum and blockcells

Modifying Enqueue Response and Receive ADD Response with seqNum, RC, blocking cells and states

Implement Receive ACK Response

Fix Bug: Packets are always picked from the top of the queue instead of from the bottom.o The behaviour is of an stack instead of FIFO. Confirm with Malisa

Modfiying Active Cell for manage 6top packages

Add 6top states in TX done

Modify 6top functions in RX done

Adding new states for DELETE

Combine in sixtop_receive_RESPONSE and sixtop_receive_RESPONSE_ACK both ADD and DELETE

Add functions _sixtop_receive_DELETE_REQUEST and _sixtop_enqueue_DELETE_REQUEST

Edit states in activeCell

Edit tsch_removeCells

Modify txDone and rxDone

Fix tsch_removeCells

By default, 6top messaging is enabled

By default Gui is on. Add two more SHARED cells

Added time-out. Remove RESPONSE from previous transation if new REQUEST comes in.

Resolved randomness by introducing sorting. Introduced tx and rx for each neighbor. Fixed removing of timer event.