Remove git directories before incremental caching
Cache the value we get from #version_for_cache
Clean up health check code
Define Logger#inspect and Logger#to_s for less messy output
Improve exception error when a software is missing
Add a config option for software_gems
Add a config option for local_software_dirs
Use the new configuration options when loading softwares
Refactor the way projects are loaded
Exclude build_version from shasum computation

Some build_version's are based off of a timestamp. Since build_version is used
in the shasumming at the project level (which is then used at the software
level), any project using a timestamp-dependent build_version would not
properly leverage git caching (it would always rebuild).

In the future, we will want to decouple build timestamps from versions.
Remove all instance of overrides_file