Merge pull request tidwall#10 from ctrix/master

More secure and user defined file permissions

Upgrade modules

Updated gjson dependency

Merge pull request tidwall#3 from gaoxinge/fix

Fix: catch os.Rename error

Updated packages

Merge pull request tidwall#2 from dim/fix/lock-contention

Avoid read-lock contention

Fix NoCopy

Optimized reads

Total rewrite of the Read operation. There is now a segment LRU
cache instead of multiple readers. This has more memory overhead,
because up to four segments may be loaded in memory at one time,
but is a ton faster and allows for forward and reverse sequential
reads.

This commit also removes the Durability option in favor of a
simpiler NoSync option.

Fix corrupt JSON format with non-UT8 binary

The JSON output format has been changed to support valid utf8 and
non-utf8 binary data. Valid utf8 has a '+' prefix and store the
data as a standard JSON string. Binary has a '$' prefix and store
the data in base64.

fixes tidwall#1