add a close() method to TemplateCache

Otherwise there's no way to close down the cache actor.
add TemplateCache.searchByName to return metadata for exact name
add repo methods to support template bundles and downloading minimal dist

- we need to check whether template bundles exist to know whether
  to publish them
- we need their URI so we can return it to the website
- we need to be able to get the minimal dist to use to make
  the bundle
- and we need a method to publish a bundle we create
add missing / to path to minimal dist
add ZipHelper so we can zip while keeping executable bits
change some log.info to log.debug in S3 repo
make bestEffortFixApplicationSecret public and allow providing the replacement value

We want to use this when cloning templates for bundling.
We'll replace the secret with some kind of FIXME value.
Merge pull request #14 from typesafehub/wip/havocp-template-bundler

Changes to support the template bundler