don't keep the lease_start in the store, always initialize it to the
current time such that a node will respect another master for at least
an entire lease_period when it wakes up.
sync store before closing tlog
ensure tlfs are synced before renaming them to their destination
add failing drop_master_while_maintenance
make sure lease expired event keep forever flowing through the state machine
Enable compiler warnings and fix resulting errors
prevent slave from ignoring duplicate message from master
Merge pull request #448 from lienboe/1.6.fix_warnings

Enable & fixup compiler warnings.
a bit more info logging
Merge #450 branch 'incubaid-sync-store' into incubaid-1.6

Conflicts:
	src/node/local_store.ml
	src/node/mem_store.ml
Merge remote-tracking branch 'incubaid/1.6' into 1.6_for_1.7_bis

Conflicts:
	logger_macro.ml
	myocamlbuild.ml
	src/client/arakoon_remote_client.ml
	src/client/arakoon_remote_client_test.ml
	src/client/benchmark.ml
	src/client/client_main.ml
	src/client/client_protocol.ml
	src/client/common.ml
	src/client/nodestream_main.ml
	src/client/remote_nodestream.ml
	src/client/remote_nodestream.mli
	src/client/remote_nodestream_test.ml
	src/inifiles/inifiles.ml
	src/main/main.ml
	src/main/replay_main.ml
	src/msg/tcp_messaging.ml
	src/msg/tcp_messaging_test.ml
	src/node/batched_store.ml
	src/node/catchup.ml
	src/node/catchup_test.ml
	src/node/collapser_test.ml
	src/node/dump_store.ml
	src/node/local_store.ml
	src/node/mem_store.ml
	src/node/node_cfg.ml
	src/node/node_main.ml
	src/node/statistics.ml
	src/node/store.ml
	src/node/sync_backend.ml
	src/node/test_backend.ml
	src/nursery/client_cfg.ml
	src/nursery/nursery.ml
	src/nursery/nursery_main.ml
	src/nursery/routing.ml
	src/paxos/master.ml
	src/paxos/mp_msg.ml
	src/paxos/multi_paxos.ml
	src/paxos/multi_paxos_fsm.ml
	src/paxos/multi_paxos_test.ml
	src/paxos/slave.ml
	src/paxos/value.ml
	src/system/drop_master.ml
	src/system/single.ml
	src/system/startup.ml
	src/tlog/compression.ml
	src/tlog/mem_tlogcollection.ml
	src/tlog/tlc2.ml
	src/tlog/tlc2_test.ml
	src/tlog/tlc_compression.ml
	src/tlog/tlogcollection.ml
	src/tlog/tlogcollection_test.ml
	src/tlog/tlogcommon.ml
	src/tlog/tlogreader2.ml
	src/tlog/tlogwriter.ml
	src/tlog/update.ml
	src/tools/crash_logger.ml
	src/tools/logger.ml
	src/tools/oUnit_XML.ml
	src/tools/server.ml
	src/tools/server_test.ml
Logging more Paxos at info level
Merge branch 'incubaid-1.6' into masterless

Conflicts:
	src/node/mem_store.ml
	src/paxos/slave.ml
	src/system/drop_master.ml
compiles with compiler warnings = "+Ae"
comment from PR
Merge pull request #460 from Incubaid/masterless

Masterless
Enabling non-LWT logging

Code mostly imported from 1.7 branch, specifically rev.
037abb4024f64af8cd86a3d57668283cefd87598, to reach a state similar as to
the one seen in rev. 186bd73659f277947cf2a95fe71bec27e15d27dc.
Logging embedded in statistics
Add `To_string` module

Implement some utilities in order to be able to write cleaner
`to_string` functions, especially of large records. Better than using
gigantic `Printf.sprintf` templates...
Use `To_string` for some `to_string` implementations