create empty /etc/logstash/conf.d directory [fixes #2188]

Fixes #2189
reinstate standalone flag and remove .bundle in vendor task

Fixes #2184
remove explicit references to ruby implementation and version

Fixes #2184
remove spool codec from default_plugins

Fixes #2167
abort artifact if plugin installation fails

Fixes #2186
short circuit simple json string generation and memoize iso8601 string

Fixes #2179
timestamp.to_iso8601 works for all platforms and faster than time format parsing

Fixes #2179
Add changelog for 1.5.beta1

Fixes #2182
Add file output fixes

Fixes #2182
Added few more fixes

Fixes #2182
Added more description

Fixes #2182
Changes after review

Fixes #2182
Added performance improvements

Fixes #2182
Adding bootstrap gem to the gem home

Fixes #2203
updated .lock files

Fixes #2203
tmp dummy lock file

Fixes #2203
do not ignore .lock files

Fixes #2203
fix jar-dependencies to version included in JRuby

Fixes #2203
solid path to logstash

Fixes #2203
gem paths settings fix & refactor

Fixes #2203