(MAINT) Update CHANGELOG and project.clj for 0.4.0 release
Merge pull request #27 from camlow325/maint/master/clj-http-client-0.4.0-release

(MAINT) Update CHANGELOG and project.clj for 0.4.0 release
lein-release plugin: preparing 0.4.0 release
lein-release plugin: bumped version from 0.4.0 to 0.4.1-SNAPSHOT for next development cycle