Limit the *SCAN command `dictScan` iterations

*SCAN will cause redis server to hang for seconds
after millions of keys was deleted by SCAN/DEL pairs
Merge pull request #1993 from xiaost/limit-scan-iter-count

Limit the *SCAN command `dictScan` iterations
luaRedisGenericCommand() cached argv handling simplified.

As discussed in issue #1945.
Sentinel: fix computation of total number of votes.

The code to check the number of voters was never updated to follow the new
Sentinel specification, so the number of voters was computed using only
the set of Sentinels that provided a vote.

This means that there is a changing majority on partitions, even if
usually the issue is not triggered because of the configured quorum
check (what was broken was the other implicit check that requires anyway
half of the known sentinels to agree in order to start a failover).
Sentinel sentinelGetLeader() top comment improved.
Improve disable save comment in redis.conf

Closes #1897
Remove surplus double quotes

Closes #1877
Update linenoise accessory files

The core linenoise code was being backported, but not
the README or example.  It's less confusing for users
if everything matches across directories.

Fix inspired by @thrig

Closes #1872
Fix many small typos

Closes #1871
Fix incorrect comments

error != success; and 0 != number of bytes written

Closes #1806
Fix typo in redis.conf

Closes #1713
Fix typo

Closes #1682
Fix typo in 00-RELEASENOTES

Closes #1673
Fix typo

Closes #1544
Fix typo: ad -> and

Closes #1537
Fix typos

Closes #1513
Grammar and typo fixes in redis.conf

Closes #1441
Fix typo in redis.h

Closes #1386
Fix on-place -> in-place

Closes #1373
Fix hash table size in comment for dictScan

Closes #1351