Upgrade to DropWizard 5.0.0-alpha. Also, minor imports cleanup#16

cml37 wants to merge 2 commits intoTomCools:mainTomCools/dropwizard-websocket-jsr356-bundle:mainfrom

cml37:update-to-dropwizard-5.0.0-alphacml37/dropwizard-websocket-jsr356-bundle:update-to-dropwizard-5.0.0-alphaCopy head branch name to clipboard