WIP: Add keep epoch env var no global rtn&fix issue 74&81

Fixes the following:

• fix issue xx - add option to strip epoch from package name
• fix issue 74 - don't overwrite existing system repos (when installing the Tor Debian repo, for example)
• fix issue 81 - (allow installation of non-PPA repos that don't match DISTRO_BINARY_COMPAT)

NOT READY

• some code clean ups
• dont ask for repo file name
• make sure ppa2pup and ppa2pup_gawk both get the fixes