MailHog v1.0.0

There's still outstanding PRs and issues which haven't been addressed in this release.

This is to get the updated release out with the latest code, since 0.2.1 is getting very stale!

• Bump release to 1.0.0
• updated mgo dependency
• temporarily remove vendor directory, because of some build issues
• Fix #117 - add info about proxies
• Fix #146 - keep tags on docker hub
• Fix #148 and mailhog/storage#7 - leading \r\n in maildir storage
• #113 - better support RFC support for headers
• #118 - optimise Dockerfile for automated builds, thanks @blueimp
• #122 - add -version flag, thanks @swordbeta
• #123 - add .gitignore, thanks @swordbeta
• #136 - update MailHog-UI assets, thanks @sdurrheimer
• #145 - fix a link in DEPLOY.md, thanks @nnmer
• mailhog/MailHog-UI#22 and #104 - support TLS websockets in HTTPS mode, thanks @blueimp
• mailhog/MailHog-UI#23 and mailhog/MailHog-UI#24 - support multiple instances of CID, thanks @kieran and @jerbob92
• more things I've forgotten/can't find!