handle rate limiting and more repo load messages

[GaryPWhite]

Description

• more messages when loading repos
• patched edge cases where sometimes no message would occur
• rate limiting will now wait to continue loading repositories (before it would fail and continue to the next repo, making large load jobs very difficult)
• allowed for use of a proxy when checking internet access (http_proxy/HTTP_PROXY is standard in many libraries, including the one in use here)

Future enhancements could include skipping validation on github until checking that a given repo is not in the database -- that's a problem for another day.

Notes for Reviewers

Signed commits

• Yes, I signed my commits.

[sgoggins]

LGTM.