bump version to 1.7.0

activate quota
bump version to 1.7.0

activate quota
update default mfsmaster.cfg

add QUOTA_TIME_LIMIT, NOATIME, RUN_MODE
add cluster id

make sure chunk server,shadow master and metalogger will connect
to correct master.
use uint32_t[4] for ip (prepare for ipv6)
remove UDP code
fix order of ip address
use 4 bytes for ip in remote message
use uint32_t[4] for ip in socket interface
support uint32_t[4] in exports_check
use uint_t[4] in topology_distance
use 4byte for ip in internal interface
semi-sync replication of changelog

Reply to clients after got at least one chaneglog ACK from metalogger.
Currently, only mkdir support this, will support more.
sync replication support for all modify operations
Merge branch 'dev' of dev744.prn1.facebook.com:/home/daviesliu/repo/moosefs into dev

Conflicts:
	UPGRADE
Merger conflict
Merge branch 'dev' into syncrep
change default SYNC_REPLICATION to 0 in metalogger
clear callback before client disconnect
add SYNC_REPLICATION in mfsmaster.cfg
Added double buffers and a separate thread to write changelog