FARADAY_HTTP_BACKEND now affects RssAgent and PostAgent too.
Set a global default User-Agent value via an environment variable.

Names starting with HTTP_ should be avoided in the context of Web app,
hence the rather verbose name `DEFAULT_HTTP_USER_AGENT`.
Use content_tag.
Add a hover menu to the "Agents" nav link.
Sane docker file optimized for quick rebuilds
Merge pull request #440 from knu/agents_hover_menu

Add a hover menu to the "Agents" nav link.
Tweak gem dependencies to improve platform support for *BSD and Solaris.

* ffi: pull in unreleased fixes from GitHub master on *BSD.

* tzinfo: require >=1.2.0 to gain support for *BSD and Solaris,
  eliminating the need for the tzinfo-data gem.
Merge branch 'platform_support'
Merge pull request #441 from andrewcurioso/docker

Docker image out of date
TwitterStream bugfixes

* do not run disabled `TwitterStreamAgents`
* calling `sleep` within the EM loop blocks the EM thread and thereby
  blocks the reload callback and proper shutdown of the threaded worker
* stopping the EM loop from outside of the `EM.run` blocks does not seem
  to work reliably, using a timer and checking if shutdown was requested
  works as expected
* removed unnecessary sleep at the end of the EM loop which would delay
  the shutdown of the thread
Merge pull request #442 from dsander/twitterstream-fixes

TwitterStream bugfixes
method: post was required for nav link to work
Merge pull request #443 from cantino/fix_header_prop_link

method: post was required for nav link to work
hipchat.rb expects the notify option to be a boolean
Merge pull request #446 from dsander/hipchat-notify

hipchat.rb expects the notify option to be a boolean
Show user the correct default User-Agent value.
Merge branch 'default_http_user_agent'
Add a parser type `text` to WebsiteAgent.
Support for markdown on scenario description.
update gems