sbbuilder & requiredbuilder

sbbuilder

1. Reconsider the inclusion of lines for Author, Website, License
2. Revise short-summary. Drop parenthesis, don't list pkgname.
3. Detect -noarch- packages.

requiredbuilder

1. Update requiredbuilder to latest upstream and apply relevant VL-specific patches.
2. Add some build-deps to the default blacklist.
3. Don't set versions by default.