(TK-83) Add :enable-trailing-slash-redirect option

Add new :enable-trailing-slash-redirect option to the options map
for all service functions that add handlers. When true, all
requests made to the handler without a trailing slash will be
redirected to have a trailing slash. Defaults to false.
(TK-83) Address PR feedback

Change name of `:enable-trailing-slash-redirect` option to
`:redirect-and-add-trailing-slash`. Add more explicit
explanation of this option to README.md.
(TK-83) Address further PR comments

Change name of setting to `redirect-if-no-trailing-slash`.
Change `add-context-handler` to take an options map instead of
the `follow-links?` and `enable-trailing-slash-redirect?`
arguments. Don't negate `:redirect-and-add-trailing-slash` option
when it is being passed around the code.
Merge pull request #87 from fpringvaldsen/TK-83-trailing-slash

(TK-83) Add :enable-trailing-slash-redirect option
(TK-92) Add graceful-shutdown support

Add graceful-shutdown support to the Jetty9 Webservice. Now,
when the webserver is shutdown, the server will give open
requests a chance to resolve themselves. Allow user to
configure the graceful shutdown stop timeout.
(TK-92) Address PR comments

Change timeout setting to `shutdown-timeout-seconds`.
Reduce sleep times in graceful shutdown tests.
Don't do graceful shutdown when stop timeout is set to 0 seconds.
Merge pull request #88 from fpringvaldsen/TK-92-graceful-shutdown

(TK-92) Add graceful-shutdown support
Update CHANGELOG and version for 0.8.0 release
lein-release plugin: preparing 0.8.0 release
lein-release plugin: bumped version from 0.8.0 to 0.8.1-SNAPSHOT for next development cycle
(TK-95) Ensure default timeout is 60 seconds

Fix issue wherein the default shutdown timeout was 30 seconds
rather than 60 seconds.
Merge pull request #89 from fpringvaldsen/TK-95-timeout-fix

(TK-95) Ensure default timeout is 60 seconds
Update CHANGELOG for 0.8.1 release.
lein-release plugin: preparing 0.8.1 release
lein-release plugin: bumped version from 0.8.1 to 0.8.2-SNAPSHOT for next development cycle
(TK-96) Fixes for default SSL protocols

This commit changes our default SSL protocols to include only
TLSv1, TLSv1.1, and TLSv1.2.  It also ensures that the server
is initialized with these protocols if the user doesn't specify
their own list via configuration.

Lastly, it makes sure that we use that same list of default
protocols for `add-proxy-route`, in the case where the user
has specified an explicit list of pem files for SSL but has
not specified protocols.
(TK-96) Minor cleanup to SSLContextFactory initialization
(TK-96) Break proxy tests into more `deftest`s

Debugging can be really hard when there are too many `testing` blocks
inside a single `deftest`.  This commit just breaks the proxy
tests into more `deftest`s.
(TK-96) Cosmetic fixes based on PR feedback
Merge pull request #90 from cprice404/bug/master/TK-96-default-ssl-protocols

(TK-96) default ssl protocols