Break out build caches for Docker and local

Build caching has been split up for Docker specifics
Docker now references build caches through the dsl_class_attributes
Add the beginning of the local build caching
Add tar methods
Update docker-api and dockly-util
Minor updates to docker build cache
Add tar and untar commands using RubyGems
Add local build caching plus specs
Make BuildCache specs faster
Add build cache CLI command and some fixes

Needed to fix tar implementation to shell out since no other
implementation supports filenames over 100 characters.
Needed to run a clean bundle environment to fix any issues when running
bundle commands inside dockly build caches locally.
Move to tmp/lol and ignore all in tmp
Add Dockly image
`arch_command` to build_cache, use in `s3_object`
README updates
arch_command is now parameter_command

parameter_command now allows multiples
Update README
Merge pull request #17 from swipely/enable_local_build_caches

Enable local build caches