Config directory support.
Add note re: regex tester.
Merge pull request #748 from mozilla-services/doc-regex-tester

Add note re: regex tester.
Merge pull request #747 from mozilla-services/logstreamer-dir-config

Config directory support.
Skip the obvious irrelevant files when loading heka config dir. Not a
complete solution to #750, but deals with the biggest pain point.
Merge pull request #751 from mozilla-services/exclude-config-files

Skip the obvious irrelevant files when loading heka config dir. Not a
Changelog update.
Merge branch 'versions/0.5' into dev