Rework `Multi_paxos.update_votes`

Since it wasn't immediately obvious to me what
`Multi_paxos.update_votes` did while reviewing #470, this change
attempts to simplify things by introducing a fairly generic
`Std.List.alter` function, which is then used to implement
`Multi_paxos.update_votes`, hopefully clarifying what this function does
exactly.
undo "fix qshell extension for node ips list"
backport preferred master changes from 1.7 + required dependencies
(GET_TXID, NOP, Client_main.with_connection')
limits dependencies for plugins
license headers
Merge branch 'incubaid-1.6' into backport-preferred-master

Conflicts:
	src/node/node_main.ml
Merge pull request #486 from Incubaid/backport-preferred-master

backport preferred master changes from 1.7 + required dependencies
Merge branch 'incubaid-1.6' into 1.6-for-1.7

Conflicts:
	pylabs/test/server/quick/system_tests_basic.py
	src/client/arakoon_client.mli
	src/client/arakoon_remote_client.ml
	src/client/client_main.ml
	src/client/client_protocol.ml
	src/client/common.ml
	src/client/python/Arakoon.py
	src/client/python/ArakoonClientConnection.py
	src/client/python/ArakoonProtocol.py
	src/client/remote_nodestream.ml
	src/client/stamp.ml
	src/node/backend.ml
	src/node/node_main.ml
	src/node/sync_backend.ml
	src/node/test_backend.ml
	src/paxos/master.ml
	src/tools/lwt_extra.ml
Merge pull request #477 from lienboe/ARA-66

undo "fix qshell extension for node ips list"
Add `Client_main.find_master_loop`
Attempt to make master lookup in some unit tests more resilient
Merge pull request #496 from Incubaid/unit-test-master-lookup-resilience

Enhance unit test master lookup resilience
fix universe.small_catchup.catchup.batched_with_failures failure
Merge pull request #497 from Incubaid/fix-universe.small_catchup.catchup.batched_with_failures-failure

fix universe.small_catchup.catchup.batched_with_failures failure
update META & changelog for 1.6.14
Merge pull request #498 from Incubaid/meta-changelog

update META & changelog for 1.6.14
update camltc for build_and_package CI job
Merge pull request #499 from Incubaid/update-camltc

update camltc for build_and_package CI job
explain the comments purposes (in a comment)
Merge branch 'incubaid-1.6' into incubaid-1.6-for-1.7

Conflicts:
	META
	extension/client/ArakoonClient.py
	pylabs/extensions/arakoon_ext/server/ArakoonManagement.py
	pylabs/test/server/quick/TestConfig.py