Manual merge with interDC branch
Add trigger to dwonstream vnode
I need to push to share my changes
Merge branch 'origin/causality'

Conflicts:
	src/clockSI_downstream_generator_vnode.erl
	src/floppy_app.erl
	src/floppy_rep_fsm.erl
	src/floppy_sup.erl
	src/inter_dc_recvr.erl
	src/inter_dc_repl.erl
	src/logging_vnode.erl
Merge branch 'origin/master'

Conflicts:
	include/floppy.hrl
	src/clocksi_downstream_generator_vnode.erl
	src/floppy_app.erl
	src/floppy_rep_fsm.erl
	src/floppy_rep_vnode.erl
	src/inter_dc_repl.erl
	src/logging_vnode.erl
add interdc vnodes to floppy_app
add additional functions in vectorclock
fix wrong merge
modfied interdc receiver functions
receive a list of updates at a time
replicate entire operations with one trigger
Merge branch 'origin/master'
replication automatically triggered after downstream generation
Preparing to send periodic sync clock messages to other DC.

Not working yet.
some functions for pulling updates from other DC
use tcp for communication between clusters
interdc-replication with heartbeat messages for clock synchronisation
trigger downstream automatically
Remove old and unused interdc files
check causal dependencies for heartbeat