Add keep epoch env var no global rtn&fix issue 74 (avoid overwrites in ~/sources*

This merge request combines the previous merge requests:

Merge Request #20 - Add keep epoch env var no global rtn

Merge Request #16 - Avoid Overwriting existing repos when installing a new repo

In order to simplify testing. Testing was difficult when the merge requests were separate. Testing is now much easier :)

Global returns were removed per request by Scott J