(SERVER-138) Created puppet.conf differences doc

This commit introduces a new document which contains some information
about the differences in supported settings from the `puppet.conf` file
for Puppet Server as opposed to the Ruby-based Puppet master.
(SERVER-138) Addressed PR feedback

This commit addresses some PR feedback, including:

* Reworded the language in the `ca` setting
* Added a note to the `configtimeout` setting about how Puppet agents
  still honor the setting
(SERVER-138) Set name of doc section to HttpPool-Related Server Settings

This commit changes the name of the last section in the new
`puppet_conf_setting_diffs.markdown` doc to `HttpPool-Related Server
Settings`.
(SERVER-113) Refactor whitelist logic out to ringutils

We are going to use the same whitelist logic for the new admin
endpoint that we were using for the cert-status endpoint.  This
commit refactors the logic out to the common ringutils namespace
so that we can access it from the new code.
(SERVER-167) Add documentation on `set_trace_func`

This commit adds some documentation on the use of the Ruby
`set_trace_func` function in the JRuby environment to trace events in
Ruby code when running in Puppet Server.
(SERVER-113) Add new puppet-admin-api HTTP endpoint

This commit adds a new TK service and HTTP endpoint for puppet
admin functionality.  For now, it just has a placeholder
"/hello" route, but the scaffolding is in place for wiring
in the real functionality, including:

* Support for client whitelist configuration
* Versioned routes (just /v1 for now)
(SERVER-203) Update to clj-http-client 0.4.0

This commit updates Puppet Server to utilize puppetlabs/clj-http-client
version 0.4.0.
Merge pull request #282 from camlow325/maint/master/SERVER-203-update-to-clj-http-client-0-4-0

(SERVER-203) Update to clj-http-client 0.4.0
Just fixing a spelling mistake
Merge pull request #286 from inhumantsar/patch-1

Just fixing a spelling mistake
Merge pull request #280 from cprice404/feature/master/SERVER-113-admin-http-endpoint

(SERVER-113) admin http endpoint
(SERVER-138) Fixed typo

This commit fixes one minor typo found during a PR review.
Merge pull request #272 from camlow325/maint/master/SERVER-138-puppet-conf-setting-diffs-doc

(SERVER-138) Created puppet.conf differences doc
(SERVER-167) Added language to syntax highlights

This commit adds a language to a few of the syntax highlights in the
`dev_trace_func.markdown` page.
Merge pull request #279 from camlow325/maint/master/SERVER-167-document-trace-func

(SERVER-167) Add documentation on `set_trace_func`
(MAINT) Add build & compare urls to travis template.
Merge pull request #290 from waynr/maint

(MAINT) Add build & compare urls to travis template.
(SERVER-116) Reuse client instances

Reuse HTTP client instances in the ruby code rather than creating
a new one for every request.
(maint) rename functions for clarity + consistency

Rename the three primary functions that return ring handlers to 'build-ring-handler'.
(SERVER-114) endpoint to flush environment cache

Add a new HTTP endpoint to the admin API, /v1/flush-environment-cache,
which tells the Puppet ruby code to invalidate all of its environment
caches.