Replaced <available> check with an <uptodate> check, to greatly help people working on the FBF who want the file automatically regenerated according to the changes they have made.

Restored call to summarise final BRAG status for regular platform builds.

Major packaging change to work around parallel calls - stopped zipping targets from having direct dependency on 'sf-preprocess-package-config', and instead have 'sf-zip-content' call 'sf-preprocess-package-config' if needed. Changed 'sf-prep' to call a target that wipes out the 'generated' directory. It's not perfect but it gets us going again.