[errors/formatting] Add format_exception
[errors] Clean up errors and logging
[errors] (GH-96) Output more information on errors

When updating a cached Git repo, the actual error being encountered
would be masked because the error rescued lacked proper error context.
Resolving this required adding wrapped exceptions so that the
originating error message could be supplied.
[module/forge] Disable color output from the PMT
Merge pull request #206 from adrienthebo/feature/master/gh-96-execution-failure-error

(GH-96) Improve logging, error messages, and provide error context