Bug Fixes

Fixed parsing of uncommited files in kit compilations.
When deploying or checking an environment, the correct stemcell is now
correctly detected when 'latest' version is requested. Note that this
didn't impact what stemcell was actually used (always the latest
available on the BOSH director for the given OS), but just the version
reported by Genesis.
BOSH CLI changed how its version is presented from v7.4.1 on, so this
change allows Genesis to detect the correct BOSH version again.

Improvements

Add exclude_paths key to kit.yml to exclude extraneous files from
being compiled into the kit.
Support Github Bearer Tokens by setting GITHUB_AUTH_TOKEN without
setting GITHUB_USER environment variables.