Some changes performed while doing minors...

1) Added a new --reset option that makes all the branches under control of the script to be reset to origin (integration.git) status. Plus deleting any manual/local modification in the worktree. Useful to cleanup if some branch has been processed by mistake incorrectly.

2) Better handling of "build dates". We always use "today" (in YYYYMMDD) format, but in minor and major releases, where we use "next monday" instead, so the packages are built 1-2-3 days before the official announcement. No matter of those default rules, at any moment, they can be overridden with a "--date WHATEVER_YOU_WANT" new option.

I've been using both extensively to produce next monday minors and results look ok.