bump trapperkeeper and kitchensink dependencies
Merge pull request #23 from KevinCorcoran/bump-TK-and-KS-versions

bump trapperkeeper and kitchensink dependencies
update CHANGELOG.md for 0.5.1 release
Merge pull request #24 from KevinCorcoran/0.5.1-release

update CHANGELOG.md for 0.5.1 release
lein-release plugin: preparing 0.5.1 release
lein-release plugin: bumped version from 0.5.1 to 0.5.2-SNAPSHOT for next development cycle
(TK-2) Rename `:config` atom to `:state`

We need a place to store the original configuration data in the
context map, and the logical name for that is `:config`; we were
using that for another purpose (to store an atom that had some
mutable state).  This commit simply changes the existing uses
to use the key `:state` instead, which is probably a bit more
accurate of a description of what we're doing, and also frees
us up to be able to use `:config` to store the actual config
in subsequent commits.
(TK-2) Add in prismatic schemas and tests for configuration objects

This commit adds prismatic schema definitions and tests for all
of the objects making up the jetty9 configuration.  It doesn't
actually wire the schemas into the code yet.
(TK-2) Remove old `configure-webserver` functions

This commit removes all of the old configuration functions and
ports the code to use the new prismatic schema representations
of the config data.
(TK-2) Simplify management of state relating to handlers
(TK-2) Port `has-handler?` and `has-state?` over to prismatic schema
(TK-2) Rename `has-webserver?` to `started?`, cleanup
(TK-2) Change `proxy-target?` to schema, other misc cleanup
(TK-2) Reorganize core namespace

This commit doesn't contain any code changes; it simply re-orders
the functions and adds some pragmas to try to make things a bit
more organized.